Seaquel
SQL Server error code

SQL Server error 7906

SQL Server raises error 7906 at severity 16, which marks a problem with the query or data that you can correct.

Database error: The file "%.*ls" is not a valid FILESTREAM file in container ID %d.
Msg7906
NameDBCC2_FS_INVALID_TOP_LEVEL_FILE
Severity16
Group7000–7999

What it means

Except for some special files such as, 'filestream.hdr', no files should be found directly under the Filestream dataspace.

Source: Database Engine events and errors