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V26.0 Every time I open I get message msls31.dll is not a valid image

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Every time I open Firefox or a second window/tab I get error message " C:\windows\system32\msls31.dll is not a valid image " I have verified I do have that file, in that directory. It doesn't cause a problem, other than I have to acknowledge it every time. Running Windows XP., sp3. I believe the problem first occurred after I updated Firefox to V 26.0

Every time I open Firefox or a second window/tab I get error message " C:\windows\system32\msls31.dll is not a valid image " I have verified I do have that file, in that directory. It doesn't cause a problem, other than I have to acknowledge it every time. Running Windows XP., sp3. I believe the problem first occurred after I updated Firefox to V 26.0

All Replies (8)

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Try to disable hardware acceleration in Firefox (you need to close and restart Firefox).

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Is it always the same page or site when this error occurs, or does it happen with any link you open in a new tab or new window regardless of the site?


I'm not sure why Firefox is accessing this particular file, but if you are not able to find another source of the problem, you could use the Windows "system file checker" to check for possible corruption.

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No particular page. It starts when I click on the Firefox icon, when I acknowledge the error, then Firefox opens. as long as I stay in that window, no problem. But if I open another window, error pops up again. SFC didn't say it found any problems, so I guess it didn't ?

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Hi mickeyk, how are you opening the second window, and does the method make any difference?

  • Firefox icon on the desktop/task bar
  • Ctrl+n
  • right-click a link > Open Link in New Window
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Mostly, I'll click a link to something that opens another window.

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Maybe try the Windows XP forum here:

http://windowssecrets.com/forums/

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Actually, if you haven't already, could you try Firefox's Safe Mode? That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?