After a bunch of investigations our devs have fixed the crash itself in 5.7 which is coming soon.
What you could try. Ensure that you have applied all Windows Updates. If it's still crashing after that then open up Internet Explorer
- On the Internet Explorer Tools menu, click InternetOptions.
- In the InternetOptions dialog box, click the Advanced tab.
- In the Security category, check Use TLS 1.0, Use TLS 1.1, and Use TLS 1.2 (if available).
- Note It is important to check consecutive versions. Not selecting consecutive versions (e.g. checking TLS 1.0 and 1.2, but not checking 1.1) could result in connection errors.
- Click OK
And try again to Login after a restart of Lr Desktop.
Hope that helps
Guido