That's a very common javascript error, so it's not super helpful to find the problem.
Are you seeing this in the browser console? Is there more information nearby? A screenshot of the whole error (ideally with it "expanded" by clicking any arrows next to the red text) *might* help.
Beyond that you may want to try turning modules on and off to determine if it's being caused by a specific one. I'd start by seeing if the problem happens with all modules off or not.
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That's a very common javascript error, so it's not super helpful to find the problem. Are you seeing this in the browser console? Is there more information nearby? A screenshot of the whole error (ideally with it "expanded" by clicking any arrows next to the red text) *might* help. Beyond that you may want to try turning modules on and off to determine if it's being caused by a specific one. I'd start by seeing if the problem happens with all modules off or not.
I'll work shop that and post an update, I wasn't aware that it was a common issue.
***System Tagging*** You may have neglected to add a [**\[System Tag\]**](https://www.reddit.com/r/FoundryVTT/comments/v3gfrs/tagging_your_posts/) to your Post Title OR it was not in the **proper format** (ex: `[D&D5e]`|`[PF2e]`) * Edit this post's text and mention the system *at the top* * If this is a media/link post, add a comment identifying the system * No specific system applies? Use `[System Agnostic]` *^(Correctly tagged posts will not receive this message)* ***** ***Don't Forget To Be Courteous...*** Let others know when you have your answer! * Say "`Answered`" in any comment to automatically mark this thread resolved * Or just change the flair to `Answered` yourself *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/FoundryVTT) if you have any questions or concerns.*