Hi David.

Yes, you can safely change the key index field maximum number in an Access field from Number Integer to Number Long Integer. The change did not affect existing records, fields, or data. I was able to append new records to existing tables without any errors or problems.

I went from a maximum number of 32,767 in the field to 2,147,483,647. That allowed me to add more than 32,767 records to my Access database without error.

Prior to making that change, I imported up to 32,767 records, but suddenly got an error message indicating that the remainder of my imported records would be ignored.

I made the change in several tables where that same productID field appeared. Everything works fine and I now have over 38,000 records in my Access database.

Have a good day!