Proton Main web browser login requires UserName & PW on its login screen. Lastpass handles this fine. Then Proton Mail displays a 2nd login screen for Mailbox PW. If I enter it manually and complete my login, Lastpass will prompt me to save the Mailbox PW. If I accept, then it overwrites the login PW with the Mailbox PW and I can not login again. This is very serious. Can it be fixed? Can Lastpass store a 2nd password for a site? If not, can I have it not prompt me on saving the 2nd pw?
With multi-page login processes LastPass can have some trouble with logging in due to these multiple pages. Could you try deleting all entries for the site from your Vault, then re-adding using the Save All Entered Data method to see if that works?
I followed your directions but I cannot get Lastpass to fill in the 2nd screen that has the "Decrypt Mailbox" form and the "Mailbox password" field. It keeps wanting to use the LoginPassword for the MailboxPassword. (There are 2 passwords to log into Proton Mail; the login pw (1st form) and the mailbox pw (2nd form).
Can you try and create a Proton Mail account and see if you can get it to work? I find this incredibly frustrating to have to open up Lastpass Vault, search for this Proton Mail account, edit it, copy and paste the Mailbox PW into the "Mailbox password" field on the Proton Mail's 2nd form ("DECRYPT MAILBOX") to login. Then Lastpass nags me to save the password I just entered. If I accidentally save it, it will overwrite the login pw with the mailbox pw I just entered. Now I've lost the login pw. Sheesh!
I even added a new field to this Lastpass entry called "Mailbox password" for the form "DECRYPT MAILBOX" (which is what appears on the Proton Mail's 2nd login form) and entered the Mailbox Password as the value. It still doesn't work.
I can't believe I'm the only one using Lastpass with Proton Mail. A video would help immensely if you or someone else has the time. Either that, or send me a brick wall so I can bang my head against it. LOL
Thanks for giving that a try. I found a guide from ProtonMail with some specific directions on how to make logging in work with LastPass and the Decrypt Mailbox field, could you try these steps to see if that works? https://protonmail.com/support/knowledge-base/last-pass/