The following error message is displayed when the Symantec Mail Security for Microsoft Exchange installer is run:

Failed to enable ASP.NET web extensions. Installation will not continue

• A Microsoft Process Monitor log shows the following errors accessing the IIS metabase.

Here the iisext.vbs script is starting:

5:01:01 PM cmd.exe 11236 Process Create C:\Windows\System32\cscript.exe SUCCESS PID: 8144, Command line: C:\Windows\System32\cscript.exe  C:\Windows\System32\iisext.vbs //B //Nologo /EnExt "ASP.NET v2.0.50727" example.com\exampleuser

Later on in the process monitor log access to the IIS metabase is denied:

5:01:01 PM wmiprvse.exe 2648 CreateFile C:\Windows\System32\inetsrv\MBSchema.bin.00000000h ACCESS DENIED Desired Access: Generic Read, Disposition: Open, Options: Synchronous IO Non-Alert, Non-Directory File, Random Access, Attributes: n/a, ShareMode: Read, Write, AllocationSize: n/a, Impersonating: S-1-5-21-2000478354-1960408961-725345543-59468 NT AUTHORITY\NETWORK SERVICE
5:01:01 PM wmiprvse.exe 2648 CreateFile C:\Windows\System32\inetsrv\MBSchema.bin.00000000h ACCESS DENIED Desired Access: Read Attributes, Delete, Disposition: Open, Options: Non-Directory File, Open Reparse Point, Attributes: n/a, ShareMode: Read, Write, Delete, AllocationSize: n/a, Impersonating: S-1-5-21-2000478354-1960408961-725345543-59468 NT AUTHORITY\NETWORK SERVICE
5:01:01 PM wmiprvse.exe 2648 CreateFile C:\Windows\System32\inetsrv\MBSchema.bin.00000000h ACCESS DENIED Desired Access: Delete, Disposition: Open, Options: Non-Directory File, Open Reparse Point, Attributes: n/a, ShareMode: Read, Write, Delete, AllocationSize: n/a, Impersonating: S-1-5-21-2000478354-1960408961-725345543-59468 NT AUTHORITY\NETWORK SERVICE

Then the script is ending with an error code of -2147024891 decimal.  Translated to hexadecimal it is 0x80070005 which is "access denied".

5:01:01 PM cscript.exe 8144 Process Exit SUCCESS Exit Status: -2147024891, User Time: 0.0156001 seconds, Kernel Time: 0.2496016 seconds, Private Bytes: 5,693,440, Peak Private Bytes: 8,065,024, Working Set: 8,953,856, Peak Working Set: 13,217,799 example.com\exampleuser