What are index.dat Error Messages?

Dynamic Link Library index.dat Errors

index.dat is considered a type of Dynamic Link Library (DLL) file. Dynamic Link Library files, like index.dat, are essentially a "guide book" that stores information and instructions for executable (EXE) files - like mighost.exe - to follow. These files were created so that multiple programs (eg. Foobar2000) could share the same index.dat file, saving valuable memory allocation, therefore making your computer run more efficiently.

Unfortunately, what makes DLL files so convenient and efficient, also makes them extremely vulnerable to problems. If something happens to a shared DAT file, either it goes missing or gets corrupted in some way, it can generate a "runtime" error message. Runtime is pretty self-explanatory; it means that these errors are triggered when index.dat is attempted to be loaded either when Foobar2000 is starting up, or in some cases already running. Some of the most common index.dat errors include:

• Access Violation at address - index.dat.
• index.dat could not be found.
• Cannot find C:\Users\Tester\AppData\Roaming\foobar2000\playlists-v1.4\index.dat.
• Cannot register index.dat.
• Cannot start Foobar2000. A required component is missing: index.dat. Please install Foobar2000 again.
• Failed to load index.dat.
• The application has failed to start because index.dat was not found.
• The file index.dat is missing or corrupt.
• This application failed to start because index.dat was not found. Re-installing the application may fix this problem.

Your index.dat file could be missing due to accidental deletion, uninstalled as a shared file of another program (shared with Foobar2000), or deleted by a malware infection. Furthermore, index.dat file corruption could be caused from a power outage when loading Foobar2000, system crash while loading index.dat, bad sectors on your storage media (usually your primary hard drive), or quite commonly, a malware infection. Thus, it's critical to make sure your anti-virus is kept up-to-date and scanning regularly.

How to Fix index.dat Errors in 3 Steps (Time to complete: ~5-15 minutes)

If you're encountering one of the error messages above, follow these troubleshooting steps to resolve your index.dat issue. These troubleshooting steps are listed in the recommended order of execution.

To begin System Restore (Windows XP, Vista, 7, 8, and 10):

1. Hit the Windows Start button
2. When you see the search box, type "System Restore" and press "ENTER".
3. In the search results, find and click System Restore.
4. Please enter the administrator password (if applicable / prompted).
5. Follow the steps in the System Restore Wizard to choose a relevant restore point.
6. Restore your computer to that backup image.

If the Step 1 fails to resolve the index.dat error, please proceed to the Step 2 below.

You can uninstall Foobar2000 software by following these instructions (Windows XP, Vista, 7, 8, and 10):

1. Hit the Windows Start button
2. In the search box, type "Uninstall" and press "ENTER".
3. In the search results, find and click "Add or Remove Programs"
4. Find the entry for Foobar2000 1.4.4 and click "Uninstall"
5. Follow the prompts for uninstallation.

After the software has been fully uninstalled, restart your PC and reinstall Foobar2000 software.

If this Step 2 fails as well, please proceed to the Step 3 below.

Foobar2000 1.4.4

Piotr Pawlowski

When the first two steps haven't solved your issue, it might be a good idea to run Windows Update. Many index.dat error messages that are encountered can be contributed to an outdated Windows Operating System. To run Windows Update, please follow these easy steps:

1. Hit the Windows Start button
2. In the search box, type "Update" and press "ENTER".
3. In the Windows Update dialog box, click "Check for Updates" (or similar button depending on your Windows version)
4. If updates are available for download, click "Install Updates".
5. After the update is completed, restart your PC.

If Windows Update failed to resolve the index.dat error message, please proceed to next step. Please note that this final step is recommended for advanced PC users only.

If Those Steps Fail: Download and Replace Your index.dat File (Caution: Advanced)

If none of the previous three troubleshooting steps have resolved your issue, you can try a more aggressive approach (Note: Not recommended for amateur PC users) by downloading and replacing your appropriate index.dat file version. We maintain a comprehensive database of 100% malware-free index.dat files for every applicable version of Foobar2000. Please follow the steps below to download and properly replace you file:

1. Locate your Windows operating system version in the list of below "Download index.dat Files".
2. Click the appropriate "Download Now" button and download your Windows file version.
3. Copy this file to the appropriate Foobar2000 folder location:
   
   Windows XP: C:\Documents and Settings\Bill\Local Settings\History\History.IE5\MSHist012017050920170510\
   Windows XP: C:\Documents and Settings\Bill\Local Settings\Temporary Internet Files\Content.IE5\
   Windows XP: C:\Documents and Settings\Bill\Local Settings\History\History.IE5\
   Windows XP: C:\Documents and Settings\Bill\Local Settings\History\History.IE5\MSHist012017051020170511\
   Windows XP: C:\Documents and Settings\Bill\Local Settings\History\History.IE5\
   Show 47 more directories +

   Windows XP: C:\Documents and Settings\Bill\Local Settings\Temporary Internet Files\Content.IE5\
   Windows XP: C:\WINDOWS\pchealth\helpctr\OfflineCache\
   Windows XP: C:\Documents and Settings\Bill\Local Settings\Temporary Internet Files\Content.IE5\
   Windows XP: C:\Documents and Settings\Default User\Local Settings\Temporary Internet Files\Content.IE5\
   Windows XP: C:\Documents and Settings\Default User\Local Settings\History\History.IE5\
   Windows XP: C:\Documents and Settings\LocalService\Local Settings\History\History.IE5\
   Windows XP: C:\Documents and Settings\Bill\Cookies\
   Windows XP: C:\Documents and Settings\Default User\Cookies\
   Windows XP: C:\Documents and Settings\LocalService\Cookies\
   Windows XP: C:\WINDOWS\system32\config\systemprofile\Cookies\
   Windows XP: C:\WINDOWS\system32\config\systemprofile\Local Settings\Temporary Internet Files\Content.IE5\
   Windows XP: C:\Documents and Settings\Bill\Local Settings\History\History.IE5\
   Windows XP: C:\WINDOWS\system32\config\systemprofile\Local Settings\History\History.IE5\
   Windows XP: C:\Documents and Settings\LocalService\Local Settings\Temporary Internet Files\Content.IE5\
   Windows XP: C:\WINDOWS\system32\config\systemprofile\Local Settings\History\History.IE5\MSHist012017042420170425\
   Windows Vista: C:\Users\Bill\AppData\Local\Microsoft\Windows\History\History.IE5\
   Windows Vista: C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Windows\History\History.IE5\
   Windows Vista: C:\Windows\SysWOW64\config\systemprofile\AppData\Local\Microsoft\Windows\History\History.IE5\
   Windows Vista: C:\Windows\SysWOW64\config\systemprofile\AppData\Roaming\Microsoft\Windows\Cookies\
   Windows Vista: C:\Users\Bill\AppData\Roaming\Microsoft\Windows\Cookies\
   Windows Vista: C:\Windows\System32\config\systemprofile\AppData\Roaming\Microsoft\Windows\Cookies\
   Windows Vista: C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\
   Windows Vista: C:\Users\Bill\AppData\Local\Microsoft\Feeds Cache\
   Windows Vista: C:\Windows\SysWOW64\config\systemprofile\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\
   Windows Vista: C:\Users\Bill\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\
   Windows 7: C:\Windows\System32\config\systemprofile\AppData\Roaming\Microsoft\Windows\Cookies\
   Windows 7: C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\
   Windows 7: C:\Windows\System32\config\systemprofile\AppData\Roaming\Microsoft\Windows\IETldCache\
   Windows 7: C:\Windows\SysWOW64\config\systemprofile\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\
   Windows 7: C:\Users\Bill\AppData\Local\Microsoft\Windows\History\History.IE5\
   Windows 7: C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Windows\History\History.IE5\
   Windows 7: C:\Windows\SysWOW64\config\systemprofile\AppData\Local\Microsoft\Windows\History\History.IE5\
   Windows 7: C:\Windows\SysWOW64\config\systemprofile\AppData\Roaming\Microsoft\Windows\Cookies\
   Windows 7: C:\Users\Bill\AppData\Roaming\Microsoft\Windows\Cookies\
   Windows 7: C:\Windows\System32\config\systemprofile\AppData\Roaming\Microsoft\Windows\IETldCache\
   Windows 7: C:\Users\Bill\AppData\Roaming\Microsoft\Windows\IETldCache\
   Windows 7: C:\Users\Bill\AppData\Local\Microsoft\Feeds Cache\
   Windows 7: C:\Users\Bill\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5\
   Windows 10: C:\Users\Tester\AppData\Roaming\foobar2000\playlists-v1.4\
   Windows 10: C:\Program Files\Adobe\Adobe Lightroom\Resources\LensProfiles\
   Windows 10: C:\Program Files\Adobe\Adobe Lightroom\Resources\CameraProfiles\
   Windows 10: C:\ProgramData\Adobe\CameraRaw\LensProfiles\
   Windows 10: C:\ProgramData\Adobe\CameraRaw\CameraProfiles\
   Windows 10: C:\ProgramData\Adobe\CameraRaw\LensProfiles\
   Windows 10: C:\ProgramData\Adobe\CameraRaw\CameraProfiles\
   Windows 10: C:\ProgramData\Adobe\CameraRaw\LensProfiles\
   Windows 10: C:\ProgramData\Adobe\CameraRaw\CameraProfiles\
   
4. Restart your computer.

If this final step has failed and you're still encountering the error, you're only remaining option is to do a clean installation of Windows 10.

You are downloading trial software. The purchase of a one-year software subscription at the price of $29.97 USD is required to unlock all software features. Subscription auto-renews at the end of the term (Learn more). By clicking the "Start Download" button above and installing "Software", I acknowledge I have read and agree to the Solvusoft End User License Agreement and Privacy Policy.