This issue may be caused by an authentication error during sign-in. Please try the following methods.
(For Mac) — For the Windows version, refer to the corresponding Windows FAQ

▼Method 1

Microsoft provides a “license removal tool” for Mac on their official website.
By running this tool, you can completely remove the Microsoft account license information from your Mac and then sign in again using your university Microsoft account (ending in @u or @un).

※Before running the tool, make sure to close all Office applications (e.g., Word, Excel, etc.).
※Since this is a license removal tool, if you are using the Outlook desktop app for sending/receiving emails (especially via POP), your account settings or emails may be deleted. Please back up your data as necessary and proceed at your own risk.

For detailed instructions:
How to remove Office license files on Mac
See the section: “Download and run the license removal tool.”

▼Method 2

If the issue is not resolved with Method 1, refer to the following Microsoft support page and check the section titled “For Mac devices, follow these steps:”
Microsoft 365 apps activation error “Another account from your organization is already signed in on this computer”

This issue may be caused by an authentication error during sign-in. Please try the following methods.
(For Mac) — For the Windows version, refer to the corresponding Windows FAQ

▼Method 1

Microsoft provides a “license removal tool” for Mac on their official website.
By running this tool, you can completely remove the Microsoft account license information from your Mac and then sign in again using your university Microsoft account (ending in @u or @un).

※Before running the tool, make sure to close all Office applications (e.g., Word, Excel, etc.).
※Since this is a license removal tool, if you are using the Outlook desktop app for sending/receiving emails (especially via POP), your account settings or emails may be deleted. Please back up your data as necessary and proceed at your own risk.

For detailed instructions:
How to remove Office license files on Mac
See the section: “Download and run the license removal tool.”

▼Method 2

If the issue is not resolved with Method 1, refer to the following Microsoft support page and check the section titled “For Mac devices, follow these steps:”
Microsoft 365 apps activation error “Another account from your organization is already signed in on this computer”

This issue may be caused by an authentication error during sign-in. Please try the following methods.
(For Mac) — For the Windows version, refer to the corresponding Windows FAQ

▼Method 1

Microsoft provides a “license removal tool” for Mac on their official website.
By running this tool, you can completely remove the Microsoft account license information from your Mac and then sign in again using your university Microsoft account (ending in @u or @un).

※Before running the tool, make sure to close all Office applications (e.g., Word, Excel, etc.).
※Since this is a license removal tool, if you are using the Outlook desktop app for sending/receiving emails (especially via POP), your account settings or emails may be deleted. Please back up your data as necessary and proceed at your own risk.

For detailed instructions:
How to remove Office license files on Mac
See the section: “Download and run the license removal tool.”

▼Method 2

If the issue is not resolved with Method 1, refer to the following Microsoft support page and check the section titled “For Mac devices, follow these steps:”
Microsoft 365 apps activation error “Another account from your organization is already signed in on this computer”