Slow opening any type of file (15 seconds)

For example, opening a 3 kb text file takes 15 seconds in notepad, notepad++, or vim.

These files are on the local disk. I open them with right click -> open with. Double click also takes a long time.
In notepad++ it takes the same amount of time (~15 seconds) when the program is already open.
Other types of files are also taking very long to open as well, for example an html in a browser that is already open.
Dragging the file and dropping into the window of an open program is very fast, but it is very inconvenient to have to reposition windows and folders in order to open a file.

It was working fine until a few days ago. Hard to believe something simple like this is suddenly messed up.
Anybody know what might be wrong?

Thanks.

Thanks. No, I didn't install anything recently.

Thanks Ztruker, a clean boot seems to have made the problem go away for now, and I might experiment later to see which services I can restore.

Although: as part of the clean boot I had disabled the Abode update services, and what was the first thing that popped up on the "clean boot" but the Adobe update service...

Cartoon about Adobe update manager: https://xkcd.com/1197/