The company file you have selected is Version x. Accounting Plus requires Version y files...

Troubleshooting Alert Messages Overview > Alert messages (in alphabetical order) > The company file you have selected...
If you haven't already done so, we suggest you read the Troubleshooting Alert Messages Overview.

Situation: The company file you attempted to open is from an older version of MYOB Accounting Plus, and can't be used by the version of MYOB Accounting Plus on your workstation.

Solution: Be sure the company file you attempted to open is the company file you want. If you're sure the file is correct, you'll need to upgrade the company file using the MYOB Accounting Plus Upgrade Assistant.