Unable to install any chrome extensions

[digging4roots]

I am currently running Opera 68, Win 10 64 bit, Install Chrome Extensions v 2.5.9. Tried today to load several extensions (all of the same type, HLS) and all of them failed with the error message:
Extension installation failed. Package is invalid: 'CRX_FILE_NOT_READABLE'.

Have looked on the internet, but I don't see any obvious solutions. Everyone seems to think the solution is to load the CRX file directly after enabling developer mode. That doesn't help when the file is coming from the Chrome Web Store and turning on developer mode didn't solve the error either. Do you have any suggestions?

Update: tried also to install Grammarly and Mate Translate with the same results. Apparently I am unable to install ANY Chrome extension.

[taroj1205]

I have same issue...
I also don't have solution.
I tried to uninstall Opera few times, but it didn't work.

[nightpatrol]

I have same issue

[taroj1205]

My issue solved when I tried opera beta version

[Jumperlion]

same issue for me