Microsoft has announced an incompatibility problem between Excel version 5 and Mac OS 9.

The company says that when running Excel 5 with Mac OS 9, customers will find that the Open Save and Save As commands may not respond, and users may receive "not enough memory" errors when starting Excel 5.

Microsoft is advising customers who want to run Mac OS 9 to upgrade to Excel 98, which is fully compatible with the new Mac OS.
Those who want to continue using Excel 5 should not upgrade to Mac OS 9.

The details of the incompatibility will be posted to Microsoft’s FAQ in the next few days.