<p>Ah, that's great news.</p><p>Glad I could help.  ^_^</p>

<p><span style="font-size: 10pt;">UPDATE: Fixed.  See end of post.</span></p><p>Sort of desperate for some ideas.  I've been running Mercury for years, and in the middle of the night I wake up, check my phone for messages, check my email, and my email app tells me my credentials are no good.</p><p> Restarted Mercury, then rebooted the server, changed the user password, and created a new user, and it's still refusing all IMAP logins.</p><p> Turned on the logs, <span style="font-size: 10pt;"> but it only reports that the login failed.  Since it's been running for many years, logging wasn't enabled previously and I don't know if anything here is actually different.</span></p><p> </p><p>However my troubles don't seem to end there: Mercury is also refusing -all- my aliased incoming addresses, which have also worked for years.</p><p> </p><p>So to recap: Mercury has fallen over and died.  What can I do? </p><p>----</p><p> </p><p>So the problem was the alias.mer file.  Half asleep before bed last night I had one alias entry reversed: instead of <address><user> I'd put <user><address> and it -completely- hosed the whole Mercury system.  Not just incoming mail, but logins, and all outgoing mail as well (which would always die with 'invalid from address'). SO!  Lesson learned.</p>

<p>Has the mercury.ini file (in the main Mercury folder) for some reason been damaged? If so replace it with a backup. If that's not the case you could try reinstalling the program to make sure all components are OK.</p><p> </p>

You're a few minutes late.  As updated in the OP, it was a reversed alias entry that completely borked the entire Mercury setup.  

Thanks for reporting it! David says he will<span style="font-size: 10pt;"> look into this with the </span><span style="font-size: 10pt;">aim of having a fix in the upcoming v4.81 release of Mercury.</span>