OpenPGP: private key checksum failure

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1

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I would like to set up rclone with ProtonDrive. The config is the simplest possible, providing username, password and mailbox password (no 2FA, nor OTP).
I deleted and re-configured the account, but the result is always the error below. I searched GitHub and this forum, but couldn't find a similar error message. Might well be some mistake on my side, never used rclone before, but there isn't much to err with the config.
Thank you.

What is the problem you are having with rclone?

Run the command 'rclone version' and share the full output of the command.

❯ rclone --version
rclone v1.74.2
- os/version: debian 13.5 (64 bit)
- os/kernel: 6.12.86+deb13-amd64 (x86_64)
- os/type: linux
- os/arch: amd64
- go/version: go1.26.3
- go/linking: static
- go/tags: none

Which cloud storage system are you using? (eg Google Drive)

The command you were trying to run (eg rclone copy /tmp remote:tmp)

❯ rclone lsd ProtonDrive:
2026/06/05 15:48:54 NOTICE: proton drive root link ID '': Cannot unlock key DmhC3CxwavGkU2jPcFv_82ZSRXvQ8FI4TS2QWER5J364xfgM4qB4lDq3oxn9bqOffAs-jfEb43qFII75UfJaA==: gopenpgp: error in unlocking key: openpgp: invalid data: private key checksum failure
2026/06/05 15:48:54 CRITICAL: Failed to create file system for "ProtonDrive:": couldn't initialize a new proton drive instance: failed to unlock user keys: not able to unlock any key

Paste command here

Please run 'rclone config redacted' and share the full output. If you get command not found, please make sure to update rclone.

❯ rclone config redacted
[ProtonDrive]
type = protondrive
username = my.account@protonmail.ch
password = XXX
mailbox_password = XXX
### Double check the config for sensitive info before posting publicly

Paste config here

A log from the command that you were trying to run with the -vv flag

❯ rclone lsd ProtonDrive: -vv
2026/06/05 16:28:46 DEBUG : rclone: Version "v1.74.2" starting with parameters ["rclone" "lsd" "ProtonDrive:" "-vv"]
2026/06/05 16:28:46 DEBUG : Creating backend with remote "ProtonDrive:"
2026/06/05 16:28:46 DEBUG : Using config file from "/home/lads/.config/rclone/rclone.conf"
2026/06/05 16:28:46 DEBUG : proton drive root link ID '': Using username and password to log in
2026/06/05 16:28:48 NOTICE: proton drive root link ID '': Cannot unlock key DmhC3CxwavGkU2jPcFv_82ZSRXvQ8FI4TS2WERD5H4364xfgM4qB4lDq3oxn9bqOjjAs-zgEb43qFII75UfJFnB==: gopenpgp: error in unlocking key: openpgp: invalid data: private key checksum failure
2026/06/05 16:28:48 CRITICAL: Failed to create file system for "ProtonDrive:": couldn't initialize a new proton drive instance: failed to unlock user keys: not able to unlock any key

Paste  log here
2

That error looks like Proton's OpenPGP private key cannot be decrypted with the password rclone is using. I would first check the `mailbox_password` value.

A couple of low-risk things to try:

- If your Proton account does **not** use the old/two-password mode, remove `mailbox_password` from the remote and recreate it with `rclone config`, using only the login password (plus 2FA if prompted). The rclone Proton Drive docs list `mailbox_password` as optional and specifically refer to Proton's separate mailbox password, not a repeat of the login password.

- If you do use a separate mailbox password, re-enter it through `rclone config` (or `rclone obscure`) to rule out a copy/paste or escaping issue in the config.

- Then retry `rclone lsd ProtonDrive: -vv`.

Updating to 1.74.3 is also worth doing because it is the current security release, but this particular error seems more directly related to the key-unlock/password step.

3

Thank you for the detailed message. It made me realise the `mailbox_password` is actually the decryption password and not the actual Proton Mail password.