macOS users complain about mysterious ‘TokenFactoryIframe’ file when accessing Outlook

Microsoft’s Outlook email client has been making some macOS users worried this week. When accessing Outlook in Safari, the browser downloads a mysterious “TokenFactoryIframe” file, which some people believed to be malware or something potentially dangerous to their computer. However, this doesn’t seem to be the case.

As reported by Windows Latest, most of the complaints were seen on Reddit. Multiple users claim that Safari automatically downloads the file “TokenFactoryIframe” whenever they visit Outlook through the internet. The file has no extension and cannot be opened by any app.

Although 9to5Mac was unable to reproduce the issue, there are a significant number of users who have been seeing this unknown file on their Macs after accessing Outlook.

I use Outlook on the web when I want to check my work email from home. Beginning today, every time I open Outlook on the web, my browser (Safari, on a MacBook Pro) downloads a blank text document titled “TokenFactoryIframe”. It does this over and over again without prompting me or anything. It does not happen on my work computer (Google Chrome, on a PC).

Luckily for users, the file is completely harmless as it doesn’t have any content. Microsoft confirmed to us that they are aware of an issue in Outlook where the browser attempts to force users to download an external token. More specifically, the company also confirmed that the bug only affects Safari users.

Microsoft recommends that users access Outlook through another web browser until the bug is fixed. However, a possible workaround is to block all downloads from the Outlook website by going into the Safari settings. Follow the steps below :

1. Click on the Safari menu and then click on Preferences.
2. Go to the Websites tab.
3. Select the Downloads option in the sidebar.
4. Look for Outlook and change its permission to Deny.

Have you been affected by this Outlook bug? Let us know in the comments below.