This started maybe an hour ago. I noticed one of the opera.exe processes was using 25% of the CPU (4 cores), so I closed probably "heavy" pages, but nothing changed. Opened Opera's task manager, and only thing using the CPU is the browser itself with 100%. So I close Opera and that single opera.exe process remains in memory, still consuming 25%.
I cannot open Opera again without killing that exe first. Every time I open the browser that process uses 25% and stays until I kill it. I disabled all extensions, closed all pages from my session and this is still happening. If I kill the process with Opera open, everything is shut down.
It's the most current version (74.0.3911.203), which has been running for some days now, so it's pretty strange. This is on Windows 7 x64 by the way.
I checked some other topics, I tried disabling the Cashback flag, but that didn't help.
For the record, I've been an Opera user for many many years and I don't recall this happening in the past.