Microsoft says new Outlook can't open some Excel attachments
Recorded: Dec. 1, 2025, 7:02 p.m.
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Microsoft says new Outlook can't open some Excel attachments By Sergiu Gatlan December 1, 2025 Microsoft is working to resolve a known issue that prevents some users from opening Excel email attachments in the new Outlook client. Break down IAM silos like Bitpanda, KnowBe4, and PathAI Related Articles: Attachments Sergiu Gatlan Previous Article Post a Comment Community Rules You need to login in order to post a comment Not a member yet? Register Now You may also like: Popular Stories Leak confirms OpenAI is preparing ads on ChatGPT for public roll out Microsoft: Windows updates make password login option invisible Public GitLab repositories exposed more than 17,000 secrets Sponsor Posts Overdue a password health-check? Audit your Active Directory for free Review of Passwork: Affordable Enterprise-Grade Password Manager Hackers love the holidays! Share FREE Security Awareness Training to keep family & friends cyber-safe! Upcoming Webinar Follow us: Main Sections News Community Forums Useful Resources Welcome Guide Company About BleepingComputer Terms of Use - Privacy Policy - Ethics Statement - Affiliate Disclosure Copyright @ 2003 - 2025 Bleeping Computer® LLC - All Rights Reserved Login Username Password Remember Me Sign in anonymously Sign in with Twitter Not a member yet? Register Now Help us understand the problem. What is going on with this comment? Spam Abusive or Harmful Inappropriate content Strong language Other Read our posting guidelinese to learn what content is prohibited. Submitting... |
Microsoft is currently addressing a significant issue impacting users of the new Outlook client, specifically the inability to open certain Microsoft Excel attachments. This problem, detailed in a service alert (EX1189359) and reported by BleepingComputer, began affecting Exchange Online customers since November 23rd, 2025. The root cause identified by Microsoft is an encoding error present within the names of the Excel files themselves. When these files are attached to emails and opened within the new Outlook client, the system triggers a "Try opening the file again later” error message for affected users. Notably, Microsoft has indicated that this issue extends beyond just Exchange Online customers; any user attempting to open attachments with non-ASCII characters in the file name may experience this problem. The scope of the problem remains somewhat unclear, as Microsoft has not yet released comprehensive data regarding the total number of users impacted. In response to the issue, Microsoft has deployed a fix designed to resolve the missing encoding within the file requests used to open the attachments. However, the implementation of this fix is ongoing, and it has not yet reached all affected customers. As a temporary workaround, Microsoft advises users experiencing difficulties with opening Excel attachments in the new Outlook client to utilize Outlook on the web or to manually download the files to open them on their own computer systems. This incident follows a series of other recent fixes and announcements from Microsoft. In months prior, the company addressed a major bug preventing Microsoft 365 users from launching the classic Outlook client on Windows systems, as well as a crash issue when launching the classic Outlook email client. Furthermore, Microsoft had previously addressed a problem that caused the new Outlook email client to crash when users clicked the "Switch back to classic Outlook" button. Recently, Microsoft announced that it would force install the new Outlook on Windows 10 systems starting with the February 2025 security update. These ongoing efforts demonstrate Microsoft’s commitment to resolving and mitigating issues within its widely-used productivity applications. |