TypeError: Unable to get property 'indexOf' of undefined or null reference

If you upload an image to a SharePoint Online picture library then you will get the following:

TypeError: Unable to get property 'indexOf' of undefined or null reference

It’s difficult to troubleshoot the issue but let me jot down the a quick workaround steps so you don’t have to waste your time J

Workaround: Turn on Compatibility View for all webpages

1. Right-click the window header and select Command Bar.
2. Click Page, and then click Compatibility View Settings.
3. Check the "Display all pages in Compatibility View", and click Close.

It seems that this is a known issue but I don’t have a concrete fix at this moment but will definitely share once I find it. Thanks for reading this article!

If you have any queries /questions regarding the above mentioned information then please let me know.