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Running Both .Net 1.1 and 2.0 in Windows 2003 Server 64 Bit Edition

· One min read

Problem​

Microsoft .Net Framework 1.1 and .Net Framework 2.0 don't play well together (as ASP.Net apps) on Windows 2003 Server 64 Bit Edition.

Solution​

either upgrade any ASP.Net 1.1 to 2.0 or switch to 32 bit compatibility mode. Of course switching to 32 bit mode will cause you to lose out on some performance benefits, but maybe you're okay with that (unless you're running under a very high load). Two easy steps:

  • Per http://support.microsoft.com/kb/894435 (dead link removed; SF 2025) , set IIS to 32 bit compability mode, and re-installed (with aspnet_regiis.exe) both versions in all sites.
  • Once this is done you can't get the ASP.Net tab back in IIS properties. To manually install the proper ASP.Net version in a particular app (i.e. /MyApp): in cmd line, under appropriate version in c:\windows\Microsoft.Net\Framework\{version}, type aspnet_regiis.exe -sn W3SVC/1/Root/MyApp.

Hat tip to Egil Hogholt (dead link removed; SF 2025) for the aspnet_regiis -sn suggestion.

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