SolvedMailspring ProtonMail Bridge IMAP integration

Using the newly released ProtonMail Bridge I am unable to add an IMAP account, with the error:

"Sorry, this folder does not exist. (IMAP)"

Log contents:

----------IMAP----------

* OK [CAPABILITY IMAP4rev1 STARTTLS AUTH=PLAIN AUTH=LOGIN ID APPENDLIMIT] IMAP4rev1 Service Ready
1 STARTTLS
1 OK Begin TLS negotiation now
2 LOGIN "photosphere@protonmail.ch" *********
* CAPABILITY IMAP4rev1 AUTH=PLAIN AUTH=LOGIN ID XSTOP APPENDLIMIT
2 OK [CAPABILITY IMAP4rev1 IDLE MOVE SPECIAL-USE ID XSTOP QUOTA APPENDLIMIT=26214400] LOGIN completed
3 LIST "" ""
* LIST (\Noselect) "/" "/"
3 OK LIST completed
4 ID NIL
* ID (support-url https://protonmail.com/support name ProtonMail vendor "Proton Technologies AG")
4 OK ID completed
ID (support-url https://protonmail.com/support name ProtonMail vendor "Proton Technologies AG")
����5 LIST "" "*"
HY|�� 

The Bridge is required to provide a decryption mechanism for ProtonMail. I've followed the instructions that might apply to a Thunderbird account, found here:

https://protonmail.com/bridge/thunderbird-mac#3e

Are there any related issues?

Question was originally asked in closed Issue #367, with another user experiencing the same issue.

What operating system are you using?

OSX 10.11.6

What version of Mailspring are you using?

Version 1.0.10 (1.0.10)

--

Bug?

Do you have any third-party plugins installed? If so, which ones?

None

Is the issue related to a specific email provider (Gmail, Exchange, etc.)?

ProtonMail Bridge

Feature Request?

Does this feature exist in another mail client or tool you use?

Might be a feature request, considering Mailspring seems to think that there aren't any selectable folders in the account. The bridge appears to be connecting as expected, and the Thunderbird works as expected.

53 Answers

✔️Accepted Answer

@bengotow The current problem is that mailsync attempts to create a top-level Mailspring folder, which Protonmail forbids. The highest level with write access is Folders. So for Mailspring to support Protonmail, you must change the container folder to Folders/MailSpring. Unfortunately, since mailsync is closed-source, I can't learn/provide more context or even submit a pull request to address this issue.

Other Answers:

Checked today, this is not fixed. Please make it happen 🙏

Hey! Thanks for the reply—I've actually signed up for a paid ProtonMail subscription and reproduced the problem locally, but after doing the investigation above I've decided to wait to see if the ProtonMail folks fix this. I think they should, as this probably breaks other clients as well. The parsing code we'd need to change in mailcore2 is /very/ well tested with other providers but has no specs, so I'm fairly afraid of breaking other scenarios I don't know about in the process of fixing this.

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