Follow the steps to understand the ProtonMail Backup Software
Download & Install the ProtonMail Backup Tool on Windows Computer.
The software provides advanced options to backup multiple ProtonMail accounts such as "backup multiple ProtonMail server accounts" and "connect ProtonMail server with a proxy server". Enter credentials of ProtonMail email account accordingly. You do not need to enter your regular password. Instead you can enter the App password of ProtonMail to login into the application
To get App Password for your ProtonMail account, you need to have ProtonMail Bridge. Download it from this link: https://protonmail.com/bridge/install. Once the Bridge is downloaded and installed, you will need to add your ProtonMail account to the Bridge. Click on Add a New Account button.
Enter regular Userid & Password in the ProtonMail Bridge & then click on Login button.
Now your account is successfully connected to the Bridge. By default, you will be in combined addresses mode, which means that emails from all of your addresses will be sent and received together in the same mailbox. You can click on Mailbox configuration to access the Bridge credentials for your mailbox.
You can see the IMAP Settings & SMTP Settings for your ProtonMail account. Copy Username & Password from here & Paste it into ProtonMail Backup Wizard.
Choose all the required ProtonMail mailbox folders or subfolders for the backup.
Choose the desired Output file format from 30+ saving options list.
Setup ProtonMail Backup options like change langauge, or change destination path.
It also provides various advanced filters settings for selective backup of ProtonMail mailboxes.
Initialize ProtonMail backup process in application panel.
Finally, the utility will generate a SavingLog report including all important details.