My databases have been working fine on my Windows Server 2016 standard. The database management system is Microsoft SQL Server 2017 Express.
Today I added a new table and content, all is fine. I tried to open the database diagram and received an error message:
And in case the image doesn't work, the message is:
Cannot execute as the database principal because the permission "dbo" does not exist, this type of principal cannot be impersonated, or you do not have permission. (Microsoft SQL Server, Error: 15517)
Nothing has changed on my server - no updates, etc.
I can access all the tables. When I look at the account I log in, I can see I am a the database owner, which other posts suggest to do - but I wasn't previously so unsure as to why this would help.
This issue affects every single database I have.
The only difference is I now create a daily back up from a scheduled task with the following script
BACKUP DATABASE DBName TO DISK = N'C:\Program Files\Microsoft SQL Server\MSSQL13.SQLEXPRESS\MSSQL\Backup\DBName .bak' WITH NOFORMAT, INIT, NAME = N'DBName Backup', SKIP, NOREWIND, NOUNLOAD, STATS = 10
The result of
SELECT ORIGINAL_LOGIN(), USER_NAME(), SUSER_SNAME();