SQL Server backup compatibility is forward-only: an older engine cannot restore a BAK produced by a newer engine. A version-aware database conversion is required instead of a direct RESTORE.
What to do when SQL Server says the backup version is incompatible
Keep the original backup unchanged. Restore or inspect it on a compatible newer SQL Server, rebuild the database on a new older-version target, copy the data and supported objects, then create and test a target-native BAK.
Why the restore is rejected
Newer SQL Server engines can introduce metadata, storage structures, and features that older engines do not understand. A .bak file is a physical representation of those pages, so changing COMPATIBILITY_LEVEL cannot make it readable by an older engine.
What does not solve the problem
Generate Scripts, Import/Export, and a direct RESTORE each have important gaps. They can omit constraints, indexes, identity values, programmable objects, or data-integrity evidence when used without a controlled process.
The supported conversion path
Inspect the source in read-only mode, create a clean target schema, stream rows in verified batches, rebuild supported modules, audit the result, and generate a native BAK on the target engine.
Need a safe SQL Server conversion?
Use a guided workflow that produces a verified target database and restore-ready BAK.
Start your conversion