When you create VM from a captured image, the drive letters for data disks may not preserved. For example if you have system database files on E: drive, it may get swapped to H: drive. If this is the case, SQL Server can’t find system database files and will not start. If the driver letter mismatch occurs on user database files, then the user databases will not recover. After VM is created, you just need to go to disk management to change the drive letters to match your original configuration.
Read the whole thing if you’re thinking about copying your on-premise server to an Azure VM.