I get this when trying to start it. After several reboots...
Did you have any Microsoft updated installed in the last week or so?
Yup. All the mandatory ones. Mandatory as in there's no choice, discussion, option, or request to not have them installed.
You may have encountered the issues that MS recalled those patches for. I think that both MS and Esri are working on a possible solution.
I would follow the blog that we released: Meltdown and Spectre Processor Vulnerabilities | ArcGIS Blog
I know that it mentions Enterprise issues but there are other people having GeoNet threads with issues in Desktop and/or Pro.
ArcGIS Pro Crash - Suspected Windows Update
IAoInitialize Shutdown failure on x64 after last Windows Update
Retrieving data ...