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We had this customer bring in a Dell desktop for having sound everywhere but in flash player; the customer had already had two local repair shops take a look at the problem and his IT guru son — none were able to actually fix the problem.  We looked at it for a few minutes with him in the store, but eventually convinced him we should check the computer in for repairs. 

The symptoms were sound every where, but webpages using flash player.  The volume mixer did not show any other devices but the built in sound device (a realtek sound card).  Videos would download without any problems.  All the Windows Vista x64 sounds worked fine, as did any local media.

Attempted resolutions

Uninstall Flash player, and reinstalled — no effect

Flash player removal tool, and reinstall — no effect

After poking around for a little bit, we found the registry keys for sound drivers were missing from the registry.

All the sub keys under HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionDrivers32 were missing.  A post on Technet indicated that the “wavemapper” subkey being missing was often the cause of no sound in flash player.  We created a string value subkey named “wavemapper” under HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionDrivers32, with a value of “msacm32.drv.”  After a reboot, we still had no sound.  We looked under the x64 drivers registry key HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftWindows NTCurrentVersionDrivers32 and found all the subkeys here were missing too.  So we exported a known good list of both the x86 driver32 keys, and the x64 driver32 subkeys.  After importing them and rebooting, there was still no sound.  One of our tools indicated that users did not have permissions to read the registry keys, but it also show the keys existed; however regedit show the keys as still missing.  I tried creating another copy of “wavemapper” in the Drivers32 subkey, but regedit tossed up an error saying the key already existed.

All the permissions on the registry keys looked ok, but I decided to look at the effective permissions.  Luckly, I got the right account off the bat.  It turned out the Administrator account had deny “Full Control” set.  I moved up to the key higher in the tree, and found the the deny permission.  After unsetting it and rebooting, sound worked perfectly.