SQL Server service fails to start after Windows system has made compressed files to save space

Look at the log file first: Two critical errors were found.

2014-07-27 22:28:32.81 spid7s starting up database ' master '.

2014-07-27 22:28:32.90 spid7s Error: 5118, severity: 16, State: 1.

2014-07-27 22:28:32.90 spid7s file "C:\Program Files\Microsoft SQL Server\mssql10. Mssqlserver\mssql\data\master.mdf "is compressed but does not reside in a read-only database or filegroup. This file must be decompressed.

2014-07-27 22:28:32.95 spid7s Error: 5118, severity: 16, State: 1.

2014-07-27 22:28:32.95 spid7s file "C:\Program Files\Microsoft SQL Server\mssql10. Mssqlserver\mssql\data\mastlog.ldf "is compressed but does not reside in a read-only database or filegroup. This file must be decompressed.

Then remember, recently just compressed the system files, and then found the SQL Server database file , Right-click on the two files to find the properties , and then select Advanced , the compression option to remove , and finally restart the SQL Server service.