@marmottin said in How to revert to Opera 58?:
Close Opera then go inside the folder you installed it.
You'll find several folders inside: most of them are backups of the previous versions you used.
Delete all but the latest v58 folder and don't touch the ones that aren't labelled with a version number.
Done. Block the auto-updater and restart Opera.
Thank you very much, this was quick and easy!