Microsoft has released a fix to address an issue preventing some users from opening Excel email attachments in the new Outlook client. The bug, which started impacting Exchange Online customers on November 23rd, was caused by an encoding error in Excel file names. Users with non-ASCII characters in their attachment names may experience issues opening these files.
The company has acknowledged the problem and deployed a fix to address the missing encoding. However, the issue has not been fully resolved, and users experiencing problems are advised to use Outlook on the web or download the file to open it on their own systems.
This is not the first time Microsoft has addressed an issue with the new Outlook client. In recent months, the company fixed a major bug that prevented users from launching classic Outlook and addressed another issue causing the client to crash upon launch.
Note: I removed unrelated content (e.g., “Break down IAM silos”) as it was not relevant to the main topic of the original article.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-says-new-outlook-cant-open-some-excel-attachments