Access 2010-2016 Compatibility Error I was just updated to Access 2016, while my users are still at Access 2010.

I opened our database in MS Access 2016 once, didn't make any changes, and closed it out, and now all the users are having errors for ANY basic VBA code, including:

StrConv (Me.FormField, vbProperCase)
DoCmd.GoToRecord
DoCmd.RunCommand acCmdSaveRecord


etc.

However, it works fine on my end. Totally broken for all my users on Access 2010. Is there any way to fix this? I am thinking, even if I go back to Access 2010, if these are errors for code that would normally work fine in either version, how to I resolve these errors?

Tried a compact and repair, no effect.

Here's an example: In Access 2010,  when the AfterUpdate() event is triggered on a textbox that has the StrConv (Me.FormField, vbProperCase) function, it brings up the VBA debugger. 
The error is: Compile error: cannot find  project or library.

Previously, the exact same function worked fine in access 2010, and there have been no changes to this code. It works fine in a backup copy from about 15 days ago.
Community wiki answer:

That particular error message is the key:


  Compile error: cannot find  project or library


Opening the office 2010 database in 2016 removed all of the VBA references to 14.0 Object Libraries in the References menu, and replaced them with 16.0, which is not present in Office 2010.

Broken references are to be expected when the .mdb is opened in an older version. It happens when there are references to Office libraries (Word, Excel, etc). Edit the references (in the VB Editor) in the oldest version (the one that doesn't run the code).