A client needed SP3 installed for their line of business app. For some reason, the service pack failed and would not install. We found the solution in Microsoft’s forums as follows:
- Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL.1\Setup
- Locate the "Resume" REG_DWORD and change the decimal value from 1 to 0
This permitted the service pack to install properly.