アップデート後エクセルファイルが使えなくなった。

Hi yoshiro kato,

Are you saying that Excel files are now opening (or trying to open) in Reader? It sounds like the operating system's file association for Excel files may have changed. You should be able to reassociate .xls files with Excel--see the documentation for your operating system for more information.

If I misunderstood your question, please let me know.

Best,

Sara