Quick answer: Open Regedit, delete the key HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache, then reboot. That stops Windows from caching files in a way that trips up buggy software.
Here's the deal: ERROR_BADSTARTPOSITION (0x0000030A) shows up when a program tells Windows “start reading from position 0” but the file or memory buffer isn't ready. It usually means the developer wrote code that assumes data is already loaded, but it isn't. You'll see this most often in older software, like a 2015-era backup tool or a custom database app that hasn't been updated for Windows 10 or 11. The real fix is a developer patch, but you can work around it by forcing Windows to handle file reads more strictly.
Step-by-step fix
- Open Registry Editor – Press Win + R, type
regedit, then hit Enter. Click Yes if User Account Control asks. - Navigate to the key – In the left pane, go to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management. Paste the path into the address bar at the top, then press Enter. - Find the setting – In the right pane, look for a value named
LargeSystemCache. It's usually a DWORD (32-bit). If you don't see it, the error might be caused by something else – skip to alternative fixes below. - Delete the value – Right-click
LargeSystemCache, choose Delete, then click Yes. - Reboot your computer – After restarting, try running the program that gave you the error. It should work now.
After the reboot, you might notice your system feels a little faster – that's because you've disabled a caching mode that sometimes slows down random file access. If you need it back for server workloads, set LargeSystemCache to 0 instead of deleting it.
Alternative fixes if the main one fails
- Run the program as administrator – Right-click the program's .exe, choose Properties, then the Compatibility tab. Check “Run this program as an administrator.” This gives it direct file access, bypassing some iterator checks.
- Update the software – Go to the developer's website and download the latest version. The author might have patched the iterator bug.
- Use Process Monitor to find the exact file – Download Procmon from Microsoft Sysinternals. Filter by the program name, then look for the last file that gave a “BAD STARTPOSITION” result. That file might be corrupted – try reinstalling the program.
Prevention tip
Don't change the LargeSystemCache setting unless you're sure the error is triggered by software you trust. Some antivirus and backup tools rely on it, and disabling it might slow them down. The real prevention is to keep your software updated – developers fix these bugs when they know about them. Also, avoid running 32-bit programs on 64-bit Windows unless they're explicitly supported. The iterator issue is more common in old 32-bit code.