Frequently Asked Questions

Here you will find answers to common questions about AcuteFinder. First and foremost, be sure to download the latest version and install it, since many of the problems mentioned below have already been fixed. You can find the version number in the About dialog in your current instance of AcuteFinder, and use the menu option "Help -> Check for updates" to see if your upgrade protection is valid for the latest version.

If you have a question or problem that cannot be solved by the tips found here, please fill out the Support request form.

Errors during startup of AcuteFinder

Entering Registration info

Errors during scan

Manipulation of found files

General questions

Features and limits of AcuteFinder

Errors during startup of AcuteFinder

When I start AcuteFinder, I get the error: Access violation at address ...

Sometimes, the Data Execution Prevention (DEP) feature of Windows will cause AcuteFinder to crash. As a workaround, you can add AcuteFinder to list of programs that are exempt from DEP.

Just open Control Panel -> System -> Advanced (tab) -> Performance Settings (button) -> Data Execution Prevention (tab), and press "Add" to add AcuteFinder to list of programs that are allowed. Browse for C:\Program files\Hugmot\AcuteFinder\AcuteFinder.exe (or the applicable folder if you did specify a different folder during installation).

For more info, see this DEP support-page at Microsoft. Thanks to Bruce Martin for this solution.

Entering Registration info

How do I enter the user name and license key?

First, check that you are using the latest version of AcuteFinder, by using the link at the top of this page.

Simply copy the registration message to the clipboard, using Ctrl-A (Select all) and Ctrl-C (Copy) in your e-mail client. Then open AcuteFinder, and select "Registration - Enter Registration info" from the menu. The details will be filled in automatically; if not, press the "From message..." button. Then press Apply and you are set!

If you are still unable to get the key to work, a Flash-demo (500 kb) which explains clearly how to do it, might help.

If the problem persists, clear both fields (user name and license key) and press Apply and press ok for the warning dialogs that pop up. Then, repeat the process above. See the example on this picture:

Entering user name and license key

Alternatively, you can copy and paste each field and press Apply. The user name is case sensitive and should be entered exactly as shown in the registration message, including the text in parentheses if applicable. Since the License key is rather long, and some e-mail programs wrap long words, take care to paste the license key as one line.

I keep getting the error "User name or license key is not correct!"

Start by downloading and installing the latest version of AcuteFinder. Then follow the instructions above to enter the key automatically.

Another possible reason is that you did not enter/copy the user name exactly as specified in the registration message. Copy the whole name, including the data in parentheses, if applicable.

The program says that Upgrade protection has expired!

When you buy a license key, it comes with upgrade protection for 1, 2 or 5 years. If this period has expired, you can still use the program. But, if you try to upgrade to a version that was released after your upgrade protection expired, you will get this message and the program will work in demo mode.

You have two options: Either unstall the latest version and re-install the version that suits your key, or buy upgrade protection for only $10 per year, and enter the new key you will receive. Visit the History page to download older versions.

I lost my key: Can you send it again?

No problem! Just enter your e-mail address in our License key re-send form. The response is automated, so your key will be sent to you within minutes.

If your e-mail address has changed since you ordered, please use the Support form and state both the current and original e-mail addresses, and if possible, the order date and order ID to help us locate your records.

Errors during scan

Why does AcuteFinder find fewer duplicates than other programs?

AcuteFinder is very accurate, when it comes to listing of duplicate files. Some other products simply check the file names, but AcuteFinder by default only regards files as identical, if they are of the same size and have the same contents. File contents is based on CRC calculations, which are very reliable.

If you performed a scan, and the resulting list was shorter than you expected, then the reason might be:

  • Criteria may be to strict: Try to widen it by leaving file size/type/dates blank.
  • In the Settings dialog (Search tab) be sure to check only "File checksum" and "File size" as it is by default. If you check more options, like file name or file type, then fewer files will be listed, since you are asking for the same names or types.
  • See if the Skip Files/Folders in the Settings Dialog are preventing some files to be checked. You can disable some of these temporarily, by unchecking them.


Why does AcuteFinder sometimes stall during scan?

This can happen for various reasons. Most common is invalid date/time stamp on some files, corrupt files or folders, and even files/folders containing Multi-byte Character Sets, like Japanese.

You can work around this, by opening the Settings dialog, select the Progress tab, and check all log options. Then perform a scan until the program stalls. You may have to cancel it by using the Windows Task Manager (which you open by right-clicking the task bar and select "Task Manager" from the pop-up menu). Take a look at the log file, and likely you will see which folders or files are causing the error by noting the last entries in the file. Finally, you can either delete the file/folder in question manually, or add the folder to list of folders to skip in the Settings dialog.

More ideas and hints on solving scan problems can be found under Exception errors. We are constantly improving AcuteFinder to prevent scan errors to happen. Your feedback is highly appreciated, since it can help us to pinpoint such errors.

Exception error

This error can be caused by various reasons, often by a corrupt directory or archive files. Some computer viruses mess up the directory structure, and it may result in endless loops while scanning. Therefore, we recommend that you try the following steps, one at a time, and retry scanning for duplicates with AcuteFinder after each step:

  • If the error occurs during selection or delete, then try to select fewer files at a time for delete.
  • Scan your computer for viruses, using up to date virus definitions.
  • Update your Windows operating system with latest patches using or the Windows Vista updates.
  • Run disk check on your hard drive (run Windows explorer and right-click the drive, select properties, Tools tab, and press the "Check now" button.
  • Uncheck "Search in ZIP archives", since corrupted archives may cause all kinds of errors
  • Enable detailed logging using "Settings - Progress" and check all log options. After scan, view the logfile and try to determine which directory caused the error. Then you can either add it to the list of folders or files to Exclude during scans, or delete files or subfolders that may be causing the error.


Manipulation of found files

How do I select multiple files for delete?

Simply select the files you want to process, by using the mouse while pressing the control or shift keys, as when multi-selecting items in other Windows programs. If you want to select a range of files, select the first with the mouse, hold down the shift key and select the last one. Then all files between and including the two will be selected.

Next, mark those files by pressing the space bar or select "Mark selected" from the pop-up menu. Then either press the Delete-button, or select the operation you want from the toolbar, or from a pop-up menu that you can activate by right-clicking on the list.

Version 3.0 introduced various new ways of marking files for processing. You can check each file individually, use keyboard shortcuts (e.g. the arrows and spacebar) to quickly select the files you want. Options on the pop-up menu, like "Mark all but one" and "Mark all in folder" (Ctrl-D) are also very useful to mark many files at a time.

How can I quickly eliminate all duplicates?

After a successful scan, you can eliminate all duplicates by right-clicking on the list of found files, and choose "Mark all" (or "Select all") from the pop-up menu. Then all files listed will be selected, and you only have to press the Delete-key or click the delete icon on the toolbar.

However, this is method has one drawback: You are not in control of which files will be deleted and which will be retained. The reason is that AcuteFinder can't tell which file is the "original" and which is a copy, since they are all the same. Try to use the option "Mark all but one", or limit the search to specific folders or file types, and if you are using the Protection option to define which folders contain the "originals", then this method is the way to go. For more info, see the following question.

How can I prevent that the original will be deleted?

AcuteFinder lists all duplicate files, including the "original". Actually, there is no way for the program to decide which file is the original, since they are all alike! But, by selecting the option "Keep at least one instance" you can rest assured that one copy will be retained.

Additionally, you can use the protect option to protect all files found in specific top-level folders defined in the search criteria. This is very convenient to prevent deletion of folder you know to contain the "originals". See the help file for more info (under the index "protecting files"), and view the Flash-demo on using AcuteFinder (800 kb).

We recommend that you set the main log options on, so you will have a permanent record of which files were deleted/moved. Open the Settings dialog, select the Process tab, check "Log operations on file list" and "Log progress and operations to file" and define the file name.

Just try a small test to see how AcuteFinder behaves: Copy a small directory to two other test locations, scan both folders, select those files you want to delete and press the delete button. Then you can see that one copy will be left intact, usually the one at the uppermost level(s) of the first search path specified.

Why is AcuteFinder sometimes very slow during multi-deletes?

If your folders contain thousands of files, then AcuteFinder can sometimes be slow when deleting files. As a workaround, uncheck the option "Remove folders/archives that become empty after delete/move of files" in the Settings dialog's Operations tab. Then deletes will be a lot faster and you can remove the empty folders any time later, using the built-in tool (accessible via the menu option: Tools -> Find empty files/folders).

Also, consider to uncheck the option "Delete files to Recycle bin" when you are deleting many files at a time. It will speed things up considerably, but of course then you do not have the option to fetch a file in the bin.

This sloppiness has been fixed in version 3.0 of AcuteFinder.
Thanks to Robert Moore for his testing effort that revealed this weakness.

General questions

Why are there so many duplicate files on my system?

It's amazing how many extra copies of files can be found on the average computer. A real mess actually! The reasons are many; often you make a backup copy, just in case, before making serious changes, but forget to delete it afterwards. Sometimes the same file is downloaded or installed more than once, or extra copies created systematically, e.g. when sorting digital photographs by copying and renaming of files. And, sometimes files are accidentally copied to other locations, and remain there for a long time, i.e. until you find them with AcuteFinder!

On the average workstation there are thousands or even tens of thousands of files. Understandably, it is quite a chore to keep them all organized. With AcuteFinder you can find unneeded extra copies of files, that can be safely removed. This way you can reclaim the disk space they occupy and use it for more important data.

How reliable is AcuteFinder's CRC-caching mechanism?

Actually, it is quite reliable, since it reads the CRC value for a file only if the file has not changed since the last CRC-calculation took place. This means, that if location, filename, size and timestamp are the same, then the CRC-value will be read from the cache.

The MD5 checksum is never cached, so if you select the MD5 option additionally, then the MD5 checksum is calculated and used to compare the files during every run.

Some programs, like older version of HexWorkshop, do not update timestamps of modified files. So, if you are using such programs, you should either disable CRC-caching altogether or use the MD5 option to ensure that only true duplicates will be listed.

What is the difference between checksum and byte-by-byte comparison of files?

When checking if files are identical, AcuteFinder uses CRC32 or MD5 checksums. It means that each file that is possibly a duplicate of another, is read from the beginning to the end, and a unique number calculated from its contents. This number is stored and used to compare this file's contents to another file's to determine if they are truly identical. This method caluclates a long integer (32 bits) from the file and is generally considered to be very accurate, since the files also have to be of the same size. CRC32 is the standard checksum used in ZIP-archives. If you choose to use MD5 checksum (128 bits) then it is even more reliable, and you can rest assured that the files are really identical. The possibility of two different files being considered identical, when using CRC32 is about 1 in 4,294,967,296. Using MD5 checksum this figure is 1 in 3,40282 x 1038 i.e. almost astronomical.

Byte-by-byte comparison of files on the other hand, means that the contents of two files to be compared, is read byte-by-byte (in parallel) and checked for equality. AcuteFinder does not offer this option, as some of our competitors do, since it is a much slower method than using checksums. The reason is that some files need to be read more than once, if many candidates exist. Obviously, this method is not the most appropriate for huge files, like multimedia pictures, video and sound. On the plus side, this method is 100% accurate.

Features and limits of AcuteFinder

Do you support other archive types than ZIP?

No, but we plan to add support for ARC, ARJ, GZIP and RAR archives in future versions.

Will folders that are empty after delete be removed also?

Yes, from version there is an option to Remove folders/archives that become empty after delete/move of files. Just check it, and those empty and useless folders will be removed. Sometimes, small files like thumbs.db or similar files that are automatically generated by Windows, will prevent this feature to function. Then simply search for such files using regular file search tools, and delete them.

Additionally, there is a tool to find empty files or folders on your disk. A list of found items will be displayed, with the option to delete them. Even though those empty items waste very little disk space, they increase the clutter on your disk, and should therefore be deleted.

What are the size limits of AcuteFinder?

Operation of AcuteFinder is mainly limited by available memory. If CRC cache is stored to disk, it can occupy few megabytes, and log-files can grow fast if details are logged. No other files are written to disk. AcuteFinder has the following known limits:

  • Maximum supported file size for normal files = approximately 100 Gb
  • Maximum supported file size in archives = 4 Gb
  • Maximum number of files in file list = approximately 10,000 which is more of a practical limit due to the time it takes to renumber sets after delete/move/remove.
  • If multiple instances of AcuteFinder are running, and the option to store CRC to disk is checked, the CRC cache of the last instance to finish will be stored, and thereby overwrite the cache file of the previous instances.
  • AcuteFinder does not yet support handling of files/folders containing MBCS (Multi-byte Character Sets) like Japanese. Support for such character sets is planned in upcoming versions.


Does AcuteFinder support WebFolders?

Yes, it does. If you map your WebDAV or FTP site to a drive letter using Windows methods or a utility like WebDrive, then AcuteFinder works on these drives just like any other network drives.

Keep in mind though, that WebFolders can be very slow. The average speed is only about 100 kb/second, which is considerably slower than LAN speeds. Also, be sure to check the File checksum option in search criteria tab (as it is by default), since WebFolders rarely keep the original timestamps of files copied to them.

This example shows how you can map a WebFolder to a drive in Windows:

NET USE W: /user:username password

Here are few websites, that explain how to map FTP sites and WebDAV services to a drive in Windows:

CyberNotes: Map a FTP to a Drive in Windows
WindowsIT Pro: How can I map to an FTP server as a drive?

Does AcuteFinder run on Windows Vista?

Yes, it does! Just be sure to have proper access to the folder(s) you plan to scan. The best way to ensure this, is to use an Administrator account when you scan your system. Otherwise, you may have to reply to many warning messages.

Sometimes, the Data Execution Prevention feature of Vista will cause AcuteFinder to crash. See description above on how to fix it.

Please note that user files and documents are stored under the folder C:\Users instead of the C:\Documents and settings as in Windows XP. This has sometimes confused users, that are used to the Windows XP naming convention.

The default location for log-files and the CRC-cache, is the user application data folder, like C:\Users\xxxx\Application Data\AcuteFinder to ensure proper access rights to those files.

Does AcuteFinder run on Linux systems?

No, but even though AcuteFinder is not yet available on the Linux platform, you can use Samba on the Linux system to give Windows workstations access to the files kept on Linux boxes. Simply map folders as drives on a PC workstation or use UNC path for folder to search.

That way, you can find duplicate files on Linux systems, and delete or move them as you would on a PC. Keep in mind that you need proper access rights in order to scan files (read access) and to delete/move them (write access). Since Linux file names are case sensitive but on Windows they are not, performance may not be as good, since more files will be checked. Also, always use CRC or MD5 checksums due to the different case sensitivity.

Does AcuteFinder run on Mac OS X systems?

Not directly, but Mac systems now offer the option to run Windows either using dual-boot, using virtual machines, or by Windows simulation environments. AcuteFinder can run in most of these environments, but compatiblity issues may limit some of its features. For more info, click here.

Even though AcuteFinder is not yet available for the Mac OS X platform, you can use Samba on the Mac system to give Windows workstations access to the files kept on Mac boxes. Simply map folders as drives on a PC workstation or use UNC path for folder to search.

That way, you can find duplicate files on Mac OS X systems, and delete or move them as you would on a PC. Keep in mind that you need proper access rights in order to scan files (read access) and to delete/move them (write access). Since Mac file names are case sensitive but on Windows they are not, performance may not be as good, since more files will be checked. Also, always use CRC or MD5 checksums due to the different case sensitivity.

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