Common File Transfer Error Messages


Microsoft Teams has some limitations on file names. There are certain characters that are not allowed in a file name, as well as unseen spaces at the end of a file name that can cause issues when moving a file into Teams. This article will provide you with some information about illegal characters and what the error messages are telling you.

What happens if you try to copy a problematic file to Teams?
While copying files from the H: drive to Teams, you may encounter errors with certain files. For example, you might see an error pop up if the file name has characters that are not allowed in Microsoft Teams (see screenshot with examples below). 

Invalid File and Folder Name Characters
•    Common invalid characters include # % * : < > ? / | or a space at the end of the file name. 
•    These names are not allowed for files or folders: .lock, CON, PRN, AUX, NUL, COM0 - COM9, LPT0 - LPT9, _vti_, desktop.ini, any filename starting with ~$.
•    Another problem is a file path that is too long. The entire path, including the folder name(s) and the file name, must contain fewer than 400 characters.

For more information about invalid file names and how to correct errors, visit this Microsoft site.

Example of a File/Folder Name Error
The following screenshot is an example of what you see if you try to copy a folder with a problematic file from the H: drive to Teams. Notice the red X when the copy finishes. This indicates that an error occurred.

If you click on the red X and scroll through the file list, you can see which file/folder was a problem. The issue in the example below is that the folder name “Counting ” contains a space at the end of the folder name.


To fix this issue, you would need to rename the folder, then copy the folder from H to Teams.

  • To rename a file or folder in Windows, right-click on the file or folder and choose Rename from the menu.
  • To rename a file or folder on a Mac, select the file or folder and press the ‘return’ key.


Article ID: 99771
Tue 3/3/20 10:40 AM
Wed 4/28/21 10:26 AM