@burnout426 Thanks for your reply. I managed to solve (I think!) this problem - I mean, make it disappear totally - yesterday by... switching to another browser, here is how.

I was so frustrated that I indeed switched to MS Edge. I'll spare you the details of the migration, but I soon found out that Edge too was "forgetting" the credentials I was entering once I would close Edge and reopen it.

It became clear that the problem was not just Opera"s, but a system wide one (and it connected with the odd fact that another program, not a browser, had lost the credentials it had had for months. So I tried various ways to fix the Windows Credential Manager - to no avail. I ended up running the DISM command - which didn't find any problem - and then SFC, and it reported having found some problems and repaired them.

And indeed, now Edge doesn't forget the credentials I reentered for a variety of sites. I suppose - haven't checked - that Opera does too, and will now check that other program too, and will stay with Edge as my default browser.

It turns out that many other programs "forgot" the passwords they used to record - not only other browsers, but other applications.

So I ended up creating a new account, painstaikingly migrating all my data from the previous one, and this one works fine.

So whichever Windows App is responsible for this problem, it is only wrt to a specific account.

It turns out that many other programs "forgot" the passwords they used to record - not only other browsers, but other applications.

So I ended up creating a new account, painstaikingly migrating all my data from the previous one, and this one works fine.

So whichever Windows App is responsible for this problem, it is only wrt to a specific account.

@EmreTheLizard How did you specify the web site in the popup? I tried, eg, "gmail.com", "http://gmail.com", "https://accounts.google.com" - they all were recorded but display with "(LegacyGeneric)" and when I connect to that site, it prompts me with empty login/passwd fields.

Unfortunately, I found out that what I described above didn't help. I ended up contacting today the Microsoft Support (for which I have a yearly contract). The support person I spoke to in the morning reinstalled Windows (fortunately without affecting my files and the configuration). This took ca. 2 hours, no change. So I called again, and the support person I talked to in the afternoon... did the same. To no avail.

So I posted a message on the Microsoft Community page.

@burnout426 Thanks for your reply. I managed to solve (I think!) this problem - I mean, make it disappear totally - yesterday by... switching to another browser, here is how.

I was so frustrated that I indeed switched to MS Edge. I'll spare you the details of the migration, but I soon found out that Edge too was "forgetting" the credentials I was entering once I would close Edge and reopen it.

It became clear that the problem was not just Opera"s, but a system wide one (and it connected with the odd fact that another program, not a browser, had lost the credentials it had had for months. So I tried various ways to fix the Windows Credential Manager - to no avail. I ended up running the DISM command - which didn't find any problem - and then SFC, and it reported having found some problems and repaired them.

And indeed, now Edge doesn't forget the credentials I reentered for a variety of sites. I suppose - haven't checked - that Opera does too, and will now check that other program too, and will stay with Edge as my default browser.

@EmreTheLizard I tried the procedure you outlined, but it failed: I added one site to Windows Key Manager (and it recorded it well: when I closed it and reopened, it was listed there - but with a mention of "LegacyGeneric", no idea what this means), but Opera ignored it, even after having restarted it: that web site does prompt for the correct login, but no password. To make clear, it is configured to store the passwords I enter. Even before this total erasure, there were sites Opera just stopped recording the passwords (while it had in the past). Now it just doesn't show any past recorded password nor record new ones.

Also, I used NirSoft's WebBrowserPassView in order to display the stored passwords for all my installed browsers: for opera, it displayed a list of sites, their respective logins/accounjt names, but empty passwords (even after having added one in Windows Key Manager).

I tried other web sites: for some, Opera stores the password now, for some it does not (while it did in the past). This is maddening. I may drop Opera and move to Microsoft Edge: with this test site (the one I used above), it offers to record the password, it stores it, and prompts it when I exit Edge and reenter.