Getting an error when migrating to the latest UI Path build


I have been constantly getting the “Collection was modified; enumeration operation may not execute” error message.

This has happened when I upgraded to the latest version of UiPath (2023.4.3). I files I am trying to open was build using the 2022.10.4 version.

What’s the workaround this issue?


check the variables particularly list or datatables if they are used in loops and re add them also see they are not being used in loop and inside loop at the same time


Hey @Anil_G,

I have the same issue.
How am I supposed to search for what you suggest, if the project does not open?
Is there anything I can look for in the xaml files?

For me the issue came very weird.
I installed 2023.4.3 early this week.
I WAS able to open the specific project which now fails.
I did not change anything, just ran and debugged existing workflows.
I am now not able to open this project anymore. Error occurs on opening the project.

I also tried renaming project.json (which you suggested here Getting Error: Open Document Error Collection was modified; enumeration operation may not execute - #5 by Anil_G).
That leads to the Studio not reacting anymore - Need to kill it, when I try to open the renamed file.

In my case it is only libraries failing to open.
Haven’t had an issue with opening bots.

Hope someone can help.



After renaming the project.jaon you need to open the main.xaml again and not the renamed project.json…please try it


Hey Anil,

There’s no main in a library. Can I open any of the files?

When opening any of the xaml files after renaming, Studio stalls again.
Nothing happens.


Can you please tell what compatibility it is in?

Also is it possible to attach the file here


Hey Anil,

don’t understand what you mean with “compatibility”.

Do you mean only the project.json or the whole library?



If you can send whole library it would be good…you can send it personally as well if you can…

or if you have any dummy file where this issue can be replicated then you can send that as well

Compatibility- Windows -legacy, windows?


Compatibility Windows

I first try to check with a colleague who did upgrade Studio aswell recently.
Maybe it happens only on my computer. Which would make sending files obsolete.

I’ll let you know.


1 Like

Okay - Working perfectly for a colleague.
Then I’ll try to find out what is wrong with my installation.

We had an issue with our firewall when changing to 2022, causing the studio to crash on opening projects on my computer.
Maybe its similar again, although the error does not hint to it (was a timeout error with 2022).


like thomas said, i too am having difficulty opening the file. however, for unknown reasons, i could open it at times (very intermittent though) but i needed to open another copy of the file.

there are instances i rename the project.json file but in doing so i lose my settings especially the dependencies.

so could this be a bug or something with the latest UiPath release because i didn’t have the same issue when i moved up to the 2022 build.