TypeError: b is undefined TypeError: b is undefinedTypeError: a is null

Question

Hello, 

First timer on forums so hoping for luck. 
I recently migrated from SP2010 to SP2013 (ShareGate). However, some webparts have broken and showing this error. 

Error: 

TypeError: b is undefined

TypeError: b is undefinedTypeError: a is null 

I'm thinking no big deal. I'll delete the APP from site contents and just recreated the APP with the information needed (Apps: Contacts/Annoucementse/Task/etc..)

However, creating a whole new webpart and adding the app to the zone still gives me the same error. 

Server: Windows Server 2012R2 

2 app servers

2 web servers 

This is happening all over the new environment (SP 2013). I'm not a SharePoint expert so hoping someone knows what could be causing this issue?

Thank you 

Answer 1

I've encountered the same error. The source of this problem : the SharePoint 2013 Jan 2016 Updates

You must install this hotfix : https://www.microsoft.com/en-us/download/details.aspx?id=50667

Answer 2

Worked like a charm. Thank you