Updated: 22 October 2026 · Applies to: Microsoft SQL Server on Windows
When the SQL Server (MSSQLSERVER) service will not start, Windows usually shows one of these messages: "Windows could not start the SQL Server (MSSQLSERVER) on Local Computer", "The service failed to respond in a timely fashion", or "The service failed to start". Below are the most common causes and how to confirm and fix each one.
Reason 1: the service account password changed but was not updated
If a domain admin or SQL admin changed the service account's password without updating it in SQL Server's own service settings, you will see:
Windows could not start the SQL Server (MSSQLSERVER) service on Local Computer. Error 1069: The service did not start due to a logon failure.
The System event log shows an Event ID 7000 entry with "The service did not start due to a logon failure."
Fix: open SQL Server Configuration Manager and enter the correct password on the Log On tab for the service account, rather than changing it directly in Windows Services.
Reason 2: startup parameters point to the wrong file path
If the master database's files (master.mdf and/or mastlog.ldf) are missing from the path SQL Server expects, the service fails to start because master is a system database. Windows shows service-specific error code 17113. The ERRORLOG file (check SQL Server's startup parameters or the Application event log for its location) shows something like:
<Date Time> Server Error: 17113, Severity: 16, State: 1. <Date Time> Server Error 2(The system cannot find the file specified.) occurred while opening file 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\master.mdf' to obtain configuration information at startup. An invalid startup option might have caused the error. Verify your startup options, and correct or remove them if necessary.
A similar error can point at the model database instead:
<Date Time> spid9s Error: 17207, Severity: 16, State: 1. <Date Time> spid9s FileMgr::StartLogFiles: Operating system error 2(The system cannot find the file specified.) occurred while creating or opening file 'C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\modellog.ldf'. <Date Time> spid9s Database 'model' cannot be opened due to inaccessible files or insufficient memory or disk space. <Date Time> spid9s Could not create tempdb. You may not have enough disk space available.
Fix: find the correct location of the files, then either move them to where SQL Server expects them or use ALTER DATABASE to point SQL Server at their real location. If the problem is with model or tempdb, start SQL Server with trace flag 3608 (according to Microsoft's SQL Server documentation) to bring the instance up without those databases so you can repair them.
Reason 3: system database files are missing or corrupted
If files for the master or model databases are missing or corrupted, for example after a disk failure, the service will not start. The ERRORLOG names the exact database and file:
<Date Time> spid5s Starting up database 'master'. <Date Time> spid5s Error: 9003, Severity: 20, State: 1. <Date Time> spid5s The log scan number (216:72:1) passed to log scan in database 'master' is not valid. This error may indicate data corruption or that the log file (.ldf) does not match the data file (.mdf). <Date Time> spid5s Cannot recover the master database. SQL Server is unable to run. Restore master from a full backup, repair it, or rebuild it.
Fix: if master is corrupted, rebuild the master database and restore it from backup. If a different system database is affected, start SQL Server with the relevant trace flag and restore that database instead; Microsoft's SQL Server documentation covers the exact steps per database.
There are other reasons the service can fail to start; this covers the most common ones seen in practice.
