VS2013 schema compare: "Source is unavailable" when running against SQL Server 2016 Express

Question

I'm trying to run a schema comparison using Visual Studio 2013.5 with SQL Server Data Tools 12.0.50730.0 against a SQL Server 2016 (13.0.300) Express database.

I can configure the source connection OK, and when I hit 'Test Connection' in the connection properties dialog it says "Test connection succeeded."

However, when I hit 'Compare' in the schema comparison window it says "Initializing Comparison..." for a few seconds, then "Source is unavailable: "

This only happens if I use a SQL Server 2016 as the source, other servers work fine.

Is this a bug?

EDIT: I have also tried using SSDT 14.0.50730.0 in VS2015 and I get the same error.

Answer 1

In Visual Studio 2017 I had the same issue and the only solution that worked for me was:

Close Visual Studio, open it and try again :) It seems to be a caching issue. Another option is to rename the DB but that's not a nice way of workarounding this issue.

Answer 2

I was having the same problem connecting to AWS RDS instance. The only changes that I can tell caused the problem were upgrading to VS2015 and SSDT 14.0.61021.0

I added the following to the connection string and some combination of them fixed the problem:

;Connect Timeout=60;Encrypt=False;TrustServerCertificate=True;Persist Security Info=True

I figured this out by recreating the comparison then comparing the two .scmp files