SharePoint Online Calendar View Error

[Jeremy7858]

Hello SharePoint Community!

So I just migrated a calendar list from On Prem 2016 to SharePoint Online using ShareGate and it was mostly successful. There were a few columns that didn't transfer over because they were Infowise columns in On Prem. Once the migration of that list was complete I found that I got an error when trying to open the list in the calendar view. The error was "Sorry, something went wrong. An unexpected error has occurred." I tried the All Events view which is not a calendar view and everything showed up perfectly.

When I tried to create a new calendar view, it threw the same error. I tried filtering the calendar view based on indexed columns. Still no luck. From On Prem, the calendar views had a calendar overlay and they worked, this could be part of the problem, maybe it's not liking that in SPO. But I can't get in there at all to change the overlay settings because none of the calendar views will load. I created a new calendar list in SPO that is disconnected from the one giving me problems and the calendar view works perfectly. Any ideas as to what is causing this error? I'm having trouble finding relevant solutions on other forums. 

Thank you for your help!

[#2]

@Jeremy7858 

Having used ShareGate many times I don't think anyone is going to be able to give you a specific answer to why this failed without seeing it. Did ShareGate give you any warnings or errors? Having the extra columns or overlays may be the issue. If you want to get to the bottom of it then create a new on-prem calendar and add the same features and migrate it until it breaks again.  Probably a rabbit hole you don't want to go down. 

My suggestion would be to create the new calendar list with the same name and migrate the content in rather than migrate the list. Recreate anything you need to and you can complete the "migration". 

[#3]

@Andrew Hodges thanks for the response. I haven't been able to ID what happened exactly yet, but I ended up exporting the data into an excel spreadsheet and creating a new calendar with the same column names. Then I used quick edit to copy the data from the spreadsheet into the new calendar. Now the new calendar works as it should. I'll try to figure out what's going on with the old one.

[#4]

@Jeremy7858 I am having the exact same problem with the views. Did you reach out to ShareGate? Did they respond? I can enter a support ticket with them, but I suspect it's the overlays and plan to migrate content over and re-create the views/overlays. 

[#5]

@KCRyan318 Same problem here.  I'll try the spreadsheet change, but that really isn't a great solution, as we are trying to migrate all of the metadata as is.  I'll put in a ticket with ShareGate.