To reproduce:
1. Create a new project
2. Open Services tab, enable Collab
3. Push initial commit
4. Add a new script to the project
5. Open Collab Toolbar, press 'see differences' to a freshly added script(Apple File Merge has to be set as revision control)
6. Notice that:
- Collab toolbar button disappears
- Services are no longer usable
- Project window is empty(after resetting layout to default)
- Bunch of errors is thrown
(Video link in edit)

Reproducible on 2018.3 only(2018.3.0a1-2018.3.0a3)
Tested on OSX 10.13.4, 10.14 Beta (18A293u)

Note: the issue happens 6/10 times

JIRA: https://jira.hq.unity3d.com/browse/SST-4000