Saved .xlsx file cannot be opened

[DarkAngel]

After creating a file and saving it to a Microsoft .xlsx file format, I was unable to re-open it.

The error message was it had an unsupported database !

[miguel-c]

Does it open with all .xlsx files you create?
Or did it only happen with that file?
Can you find a way for us to be able to reproduce the issue?

[DarkAngel]

All .xlsx files I have created will not open.

They are pretty basic... with a formula sum to calculate the numerical content of cells

[miguel-c]

Where are the files stored at?
Do pmdx files work?