Following commands will provide you admin access for SQL Server instance. Step 1:  Run > Services.msc Step 2: Stop SQL Server (Express) Step 3: sc start mssql$sqlexpress -m -T3659 -T4010 -T4022 Step 4: sqlcmd -S [SQLInstanceName] -E Example: sqlcmd -S ComputerName\sqlexpress -E Step 5: exec SP_ADDSRVROLEMEMBER 'domainname\username', 'sysadmin' go exit Example: exec