Index Was Outside of the bounds of the Array

I have been running the robot, as a novice user, and it has been running for over a year perfectly fine. Now all of a sudden it stops processing at Row 6 and like clock work I always get the same error message. I have sorted the data, so that row 6 is different, I have resaved the data, reformatted the data and it always gives me the same following message. I had someone who is more experienced with uipath, perhaps an expert take a look via remote access via Zoom and they could not figure the problem out. They ran it multiple ways and said that nothing is wrong with the coding of the robot. It was late night on their end, so they needed to take a break. How can we resolve this? Just last month, the robot went through the entire rows, which has three columns with no problem. Could it be the website? Could it be the spreadsheet? How can I fix this?

The last wording of the error code is always; the following:
03/04/2021 08:22:31 => [Debug] 4Found
03/04/2021 08:22:31 => [Debug] 4Found
03/04/2021 08:23:05 => [Info] VerifyMC Accuracy execution ended in: 00:03:06

Here is the entire log ran at a different time…

03/04/2021 08:00:19 => [Debug] Execution started for file: DataFromVerify_MMUID
03/04/2021 08:00:21 => [Info] VerifyMC Accuracy execution started
03/04/2021 08:00:26 => [Debug] 0Found
03/04/2021 08:00:26 => [Debug] 0Found
03/04/2021 08:01:01 => [Info] o is not processed due to exception: Could not find the UI element corresponding to this selector:
[1]
[2]

Search failed at selector tag:
[2]

The closest matches found are:
[96%]
[92%]
[78%]
[76%]
[42%]
[33%]
[30%]
[30%]
[28%]
[28%]
03/04/2021 08:01:05 => [Debug] 1Found
03/04/2021 08:01:05 => [Debug] 1Found
03/04/2021 08:01:38 => [Info] w is not processed due to exception: Could not find the UI element corresponding to this selector:
[1]
[2]

Search failed at selector tag:
[2]

The closest matches found are:
[96%]
[92%]
[78%]
[76%]
[42%]
[33%]
[30%]
[30%]
[28%]
[28%]
03/04/2021 08:01:41 => [Debug] 2Found
03/04/2021 08:01:41 => [Debug] 2Found
03/04/2021 08:03:12 => [Info] is not processed due to exception: Could not find the UI element corresponding to this selector:
[1]
[2]

Search failed at selector tag:
[2]

The closest matches found are:
[96%]
[92%]
[78%]
[76%]
[42%]
[33%]
[30%]
[30%]
[28%]
[28%]
03/04/2021 08:03:16 => [Debug] 3Found
03/04/2021 08:03:16 => [Debug] 3Found
03/04/2021 08:03:49 => [Info] # is not processed due to exception: Could not find the UI element corresponding to this selector:
[1]
[2]

Search failed at selector tag:
[2]

The closest matches found are:
[96%]
[92%]
[78%]
[76%]
[42%]
[33%]
[30%]
[30%]
[28%]
[28%]
03/04/2021 08:03:53 => [Debug] 4Found
03/04/2021 08:03:53 => [Debug] 4Found
03/04/2021 08:04:26 => [Info] VerifyMC Accuracy execution ended in: 00:04:05

@Antoinette_Smith The Error seems to be happening due to a UI Element not being recognised. It would mean if there is a website or an Application being involved, the configuration of the element might have changed, and hence it might be giving out the error.

But we do know only a little detail of the process as to what is actually happening, So we cannot come to a direct conclusion yet.

If you can give out the Error Log Details in a Text file, Maybe we can find the UI Element Problem and fix it.

Here’s the error log:

RemoteException wrapping System.IndexOutOfRangeException: Index was outside the bounds of the array.
at UiPath.Core.Activities.ScopeActivity.OnFaulted(NativeActivityFaultContext faultContext, Exception propagatedException, ActivityInstance propagatedFrom)
at System.Activities.Runtime.FaultCallbackWrapper.Invoke(NativeActivityFaultContext faultContext, Exception propagatedException, ActivityInstance propagatedFrom)
at System.Activities.Runtime.FaultCallbackWrapper.FaultWorkItem.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)

RemoteException wrapping System.IndexOutOfRangeException: Index was outside the bounds of the array.
at UiPath.Core.Activities.ScopeActivity.OnFaulted(NativeActivityFaultContext faultContext, Exception propagatedException, ActivityInstance propagatedFrom)
at System.Activities.Runtime.FaultCallbackWrapper.Invoke(NativeActivityFaultContext faultContext, Exception propagatedException, ActivityInstance propagatedFrom)
at System.Activities.Runtime.FaultCallbackWrapper.FaultWorkItem.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)

Are you able to start robot in debug mode on this case when it happens? If yes you will be able to check data in variables too. Maybe robot is trying to do some data manipulation, but the format of data has change so now robot is unable to perform. Sth like split, substring etc.

Or some dynamic selector is failing now. Debug mode with failing case should help to check selectors and variables and solve this.