Hi Yvonne Langlois ,

Thank you for reaching out and reporting the issue with opening company files in Sage 50. There are several reasons why this error might occur, and we have specific articles that could help you troubleshoot and resolve this issue:

1. Checking Access Permissions: Ensure you have the necessary permissions to access the files on the network or your local computer. Learn more.

2. Network-Related Issues: If you're trying to access your company file over a network, connection issues could prevent the file from opening. Learn more.

3. File Corruption: In some cases, the company file might be corrupted, which prevents Sage 50 from opening it correctly. Learn more.

I recommend checking out these articles for detailed instructions on how to diagnose and resolve the issue. If the problem continues after following the recommended steps, please do not hesitate to contact Sage's technical support for further assistance.

Warm Regards,
Erzsi