Users of the new Outlook for Windows are running into a frustrating bug: certain Microsoft Excel attachments simply won’t open — instead, they trigger the vague error message: “Try opening the file again later.”. Here’s how to bypass the bug.
Some users are finding themselves locked out of Excel attachments in the shiny new Outlook for Windows. The issue appears to stem from an encoding bug: when an Excel file name contains non-ASCII characters, the new Microsoft Outlook for Windows fails to decode the name correctly.
Instead of spreadsheets, they’re getting a rather unhelpful error:
“Try opening the file again later.”
(Which is basically tech support’s version of “Have you tried turning it off and on again?”)
Files with non-ASCII characters in the file names (think letters with accents, special symbols, or anything that isn’t your standard A-Z) are causing Outlook to lose its nerve.
Workarounds
Until a proper fix lands, users have two “official” options:
- Switch to Outlook on the web (the good ol’ browser-based version seems unaffected).
- Download the attachment locally and open it directly from your computer like it’s 2007.
The alternative Microsoft doesn’t mention is using Outlook (classic) instead.
It all comes down to a case of mistaken identity—an encoding error is tripping up the way file names are read, leading Excel to throw in the towel. You have to wonder how an encoding error can creep into Outlook (new), it’s not like the Unicode system is a recent innovation.
Why is it taking so long to fix? Microsoft has had more than a week on this bug. Even allowing for Thanksgiving, that’s too long,
There’s a fix in the works, currently going through validation. That means the final checks before a grand rollout. Microsoft expects to begin deployment sometime this week and will provide a more specific timeline soon.
Check back on Friday, December 5, 2025 for the latest status. Hopefully by then, your Excel files will be back to opening properly.
