Microsoft Excel takes long time opening documents.

Greetings All!

I have been working on a particular user's issue with Excel for some time now and have exhausted pretty much any leads I can find or think of and would like to pose this to the group. This issue has been consistent even though we changed out a good laptop for a newer and better build; so we can rule out (I think) the PC.

The PC is a Dell Latitude 3550, Intel i5-5200 2.2GHz Processor, 8GB Memory, 64-bit Windows 7 Professional and the version of Excel in question is Office 365 (2016).

The problem is that it takes a very long time to open documents. Documents will also close down (closing all of Excel down with it) leaving no error messages and nothing in the Event Viewer that would aid in troubleshooting. While documents open, there is a message which I am not sure whether it is relevant that states "Calculating (4 processor(s))". This only affects this user. No one else has these troubles working with Excel documents. The user has the same network rights as anyone else on the staff.

The problem persists whether she opens a document residing on her computer or a network share. It happens whether she is in the office or at home connected via VPN.

Here is what we have done to troubleshoot (none of which were done for any particular reason other than to rule out):

1. Repair Office
2. Remove Office/Reinstall
3. Scan for Virus/Malware/Spyware
4. Ensure all network locations set as Trusted Locations
5. Ultimately, Performed factory Restore on NEW PC and manually loaded everything back into PC
6. Dropped new Ethernet cable run from Network Switch to PC
7. Windows Updates
8. Office Updates
9. Drivers all updated
10. Created new user on Domain
11. Created new PC profile

PCs use Microsoft Security Essentials; Servers use Trend-Micro. None of my other 100+ users have this issue. The issue cannot be duplicated by any other user. I'm pretty stumped and ready for some fresh opinions. I appreciate any help on this subject. Thank You,

Joel