I know this thread is over a year old, but I also have been running into this, too. There are times when my install of Opera works fine until I restart my computer, and then it falls into a loop of open/immediately fail and close (appearing and disappearinng on the toolbar as it does so).

When I try to run from the command line, I get this error:

dyld: warning, LC_RPATH @loader_path/../../../../../../../../../.. in /Applications/Opera.app/Contents/Frameworks/Opera Framework.framework/Versions/-OPERA-VERSION-HERE/Helpers/Opera Helper.app/Contents/MacOS/Opera Helper being ignored in restricted program because of @loader_path (Codesign main executable with Library Validation to allow @ paths)

Often uninstalling and reinstalling has no effect.

The only thing that works for me is a combination of 2 suggestions. First, per another old thread Opera endless loop of crashes:

rm -r ~/Library/Application\ Support/com.operasoftware.Opera

Then, per the suggestion above, run opera with no experiments:

/Applications/Opera.app/Contents/MacOS/Opera --no-experiments

I can only open Opera by the Terminal right now.

@leocg Thank you... I've tried doing this, but after I drag and drop Opera (and it installs), the application keeps opening/closing repeatedly--any insights on why this might be happening or how to fix it?

How can I rollback to an earlier version? Latest version doesn't provide any way to handle Flash content.

Previously, I could allow Flash from some sites via preference: opera://settings/content/flash?search=flash

But in Opera 74 (for Mac), this page no longer exists.

(Before anyone replies with "but Flash is dead" -- yes, I know. Up until this latest version of Opera, I was able to access it, and I still need that access.)

When I try to download a different installer, the 74 version is still installed. How do I back to 73?