Adobe Flash Player 11.9 r900 constantly crashes with a data execution prevention error.

Question

This happens with almost every website I go to.

Answer 1

Hi moreofless, did a separate crash dialog indicate that it was a DEP error (sometimes the Windows crash dialog will indicate this)?
In some cases a DEP error can indicate that malware is attempting to interact with Flash, or that the Flash media you were using was malicious. It may be worth running a few supplemental scans just in case. The support article has suggestions on free tools that have proven reliable for Firefox users: [[Troubleshoot Firefox issues caused by malware]].
A common problem on Windows Vista and higher is incompatibility with the protected mode feature of the Flash Player plugin. Usually this leads to frequent, unsubtle problems, so you might not have this problem, but just in case, you could disable it.
See this support article from Adobe under the heading "Last Resort": [http://forums.adobe.com/message/4468493#TemporaryWorkaround Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?]
Or if there are problems with permission, try this way:
(1) In a My Computer or Windows Explorer window, open this folder:
C:\Windows\SysWOW64\Macromed\Flash
If that folder does not exist, then you are using 32-bit Windows, and you can open the following folder instead:
C:\Windows\System32\Macromed\Flash
''(Note: This folder exists on both 32-bit and 64-bit Windows, but on 64-bit Windows Firefox uses the Flash player in the SysWOW64 folder instead.)''
(2) Check for a file named mms.cfg:
'''''Note:''' If you do not see file extensions such as .ocx, .dll, .exe, and .cfg on the files in this folder, then Windows may be hiding these from you. In order to work with file names accurately, it is best to unhide the extensions. This Microsoft support article has the steps: [http://support.microsoft.com/kb/865219].''
(A) ''If mms.cfg exists,'' drag it to your '''Documents folder''' where you can edit it without being bothered about administrator privileges
(B) ''If mms.cfg does not exist,'' open your '''Documents folder''', right-click > New > Text File and name the new file mms.cfg
(3) Open mms.cfg from Documents into a text editor such as Notepad.
Add this on its own line (I put it last):
ProtectedMode=0
Save the file and close Notepad.
(4) Hold down the Ctrl key and drag the mms.cfg file back to the Flash folder to make a copy there, keeping the original in Documents
This change will take effect once the Flash plugin is completely unloaded, which may require exiting and restarting Firefox (allow a few minutes for all the Flash processes in memory to terminate after exiting Firefox).