I got the same issue, my powerapps cannot update the table in the excel file even though I already closed the file.
I did some tests and found the issue, very much likely it is because of Onedrive Sync. below are details:
the excel file is in onedrive and my onedrive is synced with my desktop. when I open the file with excel online and close it, my powerapps cannot update a table in that file with the error: the resource is locked... I wait for about an hour and try again and it works.
I copy the file to onedrive folder of another account, which do not have desktop sync, then I connect my powerapps to the new file and it works like a champ. it will not work when I open the file by excel online but as long as I have closed it, powerapps will work.
so not sync the file you use with powerapps with desktop will avoid the issue.
I went on the same road as everyone here and closed the Sync to Desktop option and it still did the same thing. The weird thing is that if you leave it for a couple of minutes it works fine. I kept digging through on line threads and found that it might have something to do with the fact that after you succesfully write in Excel in Onedrive once, the connection keeps hanging for a while and it locks any other attempts to write in that document. After some time, the connection drops and you are able to write succesfully again.
Have not found a sollution for this yet. Any other ideas?
Fill out a quick form to claim your user group badge now!
Find out where you can attend!
Features releasing from October 2019 through March 2020
Learn how to build the business apps that you need.