Hi,
Welcome to MSDN forum.
Have you tried to open another SQL file in visual studio 2015?
If all of this have the issue, right click on the tab on an opened file-> select Close all documents, reopen .sql file. Please open an administrative CMD window and navigate to C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE and run these
commands:
devenv /safemode
It prevents all third-party VSPackages from loading when Visual Studio starts.
Besides, install the latest update(update 3) for visual studio 2015 and repair it.
Best regards,
Joyce
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