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My website was working locally on my

Win 7 64 bit machine. I then installed VS2010 opted to not upgrade to .NET 4.0

Now when i go to my site i get the following error

HTTP Error 500.0 - Internal Server Error Calling LoadLibraryEx on ISAPI filter "C:\Windows\Microsoft.NET\Framework64\v2.0.50727\aspnet_filter.dll" failed

In the event log i get

Could not load all ISAPI filters for site 'ESTORE'. Therefore site startup aborted.

The site is using "DefaultAppPool" and Enabled 32-bit Application is set to True

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up vote 1 down vote accepted

OK, a little dumb on my part. I set Enable 32 bit back to true and it worked.

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What version of .NET is associated with DefaultAppPool?

You need separate app pools for .NET 2.0 (with or without 3.0 & 3.5 assemblies) and 4.0.

(The .NET 4 installer run by VS2010 created separate 4.0 app pools, but that could be an artefact of previously having RC installed.)

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Richard, DefaultAppPool is set to v2.0.5. I didn't install the rc. Just the full version that came out the other day. – Frosty May 1 '10 at 18:38

If the Enable 32-bit flag won't work for you, try to check your ISAPI filters in IIS. I had some mysterious additional .net ISAPI filter on my dev machine that I couldn't account for in there (probably from some .net RC build I installed), and after removing/disabling it, all was working again.

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