“Primary Filegroup is Full” in SQL Server 2008 Standard for no apparent reason

Question

Our database is currently at 64 Gb and one of our apps started to fail with the following error:

System.Data.SqlClient.SqlException: Coul

Answer 1

OK, got it working. Turns out that an NTFS volume where the DB files were located got heavily fragmented. Stopped SQL Server, defragmented the whole thing and all it was fine ever since.