The database version 661 cannot be enabled. This server supports both version 655 and earlier. Downgrade path not supported

"The database version is 661 and cannot be opened. This server supports both version 655 and earlier. The downgrade path is not supported"

This problem is generally caused by different database versions.

We can use the following statement to query the database version.

Use master

Select@ VERSION

(1) 661 is the version number of sql2008 R2

   Microsoft SQL Server 2008 R2 (RTM)-10.50.1600.1 (Intel X86) Apr2 2010 15:53:02 Copyright (c) Microsoft

(2) version 655, that is, sql2008 sp1 version

  Microsoft SQL Server 2008 (SP1)-10.0.2531.0 (Intel X86) Mar 29 10:27:29 2009 Copyright (c) 1988-2008

If it is later than 1600, it indicates that only sql2008r2 is installed, and a sql2008sp1 is also installed. In this way, we can ensure that 2500 is followed.