Wendell is correct, take it from an Access vetern.

If you take an older copy of Access and just open it with the newer version of Access, things might apper to work... at first.

Later, I have experienced some strange behavior that includes using transaction VBA code or strange intermittent behavior in the front-end forms where code is involved.

Basically, create a blank Access DB with the new version.

Then Import all objects into the new one.

Key: Be sure to copy the properties such as the Start-up form.

Another bonus is that the Import will re-compress and re-index the Database far beyond the Compact and Repair.

One of our production DB has code on the front-end that links to a SQL Server back-end using DSN-Less connections with the SQL Server Native Client 11.0.

I have posted code and process for all of this on the Access-UK forums. Around 180 tables.

Our Access forms don't use the Access templates. They are bound with code that enforce complex business rules.

Every six months, we re-import into a new Database. A 150 MB front-end can compact to 90 MB for Access 2010.

An interesting feature is to import it into Access 2013, then use it as Access 2010. We are doing this to test compatibility.

The Access 2013 compacts the same DB inot about 70 MB.

Since we distribute the front-end via Citrix (SQL Server back-end) the smaller footprint speeds the startup since each users gets thier own working copy of the Production copy.

Using this format, in the past we have had 255 Access users linked to SQL Server via ICA client.

Nedless to say, the front-end must pay attention to locking files and resolving dirty records in well defined error code.

Bottom line, learn how to go through the process of Importing Access into a new blank copy.

If you post questions on the Access-UK forums - there are many professionals (some retired) who are usually happy to assist.

This site helps me as a nubie, we are always willing to return favors.