Can I safely update Windows 10?

It is best not to run Windows Update, and rather to wait for it to notify you, because the week of the month when clicking "Check for Updates" is of crucial importance. This is described in a Microsoft blog post : Windows monthly security and quality updates overview.

The updates released in the third and fourth weeks of the month, called "C" and "D", include new bug fixes and improvements for other non-security issues. These are distinct from Patch Tuesday updates from the second week of the month, which are suitably called "B" updates.

Windows Update will only install C and D updates when you go to Settings > Update & Security > Windows Update and click "Check for Updates". In Microsoft’s world, this makes you a "seeker" who wants to test these updates in advance before most Windows users get them.

The Windows 10 telemetry will detect any problem caused by these updates before they appear in the next B update, without any thank-you note for unwittingly helping Microsoft out. In other words, clicking the button on the wrong week will qualify you as a "volunteer" beta tester, and Microsoft will apologize for any problems (which will not fix those problems).

So, if you click “Check for Updates” in the third, fourth, or first week of a month, before the next B update has been released, you’ll probably get a C or D update installed on your system. If you never click “Check for Updates”, you’ll stick with the better-tested B updates (tested by others than yourself).

So the solution is simple : Do not click “Check for Updates” before the B updates have been released by Microsoft, and never after the second week of the month.

My personal advice would be to never use “Check for Updates” at all, because of the risk of forcing the installation of updates that have not yet been vetted for your computer. It's preferable to let Windows Update decide which updates are now ready and tested for your computer and software.