iOS - "Kommunikation mit der Hilfs-App nicht möglich" - no communication with helper app

[olistrut]

Summary

Can connect to a vault on Google Drive and browse, but not download/open files in iPhone files app

Please agree to the following

• I have searched existing issues for duplicates
• I agree to follow this project's Code of Conduct

System Setup

• iOS: 26.5
• Cryptomator: 3.01

Cloud Type

No response

Steps to Reproduce

I have recently set up a new vault after having used the (very old) app with a (very old) vault. This is a brand new vault and not a vault converted from an earlier vault format. The vault was setup on Linux is lives on a personal Google Drive.

Steps to reproduce:

• Connect to vault on Google Drive and enter password
• Open files app -> Cryptomator -> go into vault
• Browse vault directory structure (works)
• Click on any file (or the download button) -> error message

Expected Behavior

Ability to not only browse vault structure but being able to open or download files from vault in iOS vault app.

Actual Behavior

What works:

• I can add the vault in Cryptomator on iOS and Cryptomator verifies the password (or rejects if I enter a wrong password)
• I can browse the vault in the iOS files app and see folders and file names

What doesn't work:
If I try to open or download a file in the iOS files app, I get an error message information me that "Kommunikation mit der Hilfs-App nicht möglich" (no comms with helper app possible).

Unsuccessful attempts to fix:

• I initially had the preview app installed but also tried removing that, but that didn't change anything.
• I have also in the mean time restarted the phone, removed and re-added Cryptomator as a file source in the files app and disconnected and reconnected to the vault in the Cryptomator app. No success.

Reproducibility

Always

Relevant Log Output

Log data: 
ios.fileprovider:

2026/05/15 07:08:52:414  enumerateItems getAdapter failed with: defaultLock for identifier: NSFileProviderItemIdentifier(_rawValue: NSFileProviderRootContainerItemIdentifier)
2026/05/15 07:08:52:417  enumerateItems getAdapter failed with: defaultLock for identifier: NSFileProviderItemIdentifier(_rawValue: BF0AA7B9-3265-4031-A670-C168C27E6BAA:6)
2026/05/15 07:08:52:421  enumerateItems getAdapter failed with: defaultLock for identifier: NSFileProviderItemIdentifier(_rawValue: BF0AA7B9-3265-4031-A670-C168C27E6BAA:7)


ios:
2026/05/15 07:12:06:857  Vault BF0AA7B9-3265-4031-A670-C168C27E6BAA unlock status: Unlocked
2026/05/15 07:12:07:126  Setting trialExpirationDate was removed
2026/05/15 07:12:07:127  Setting fullVersionUnlocked was written with value true
2026/05/15 07:12:07:127  Setting hasRunningSubscription was written with value false

Anything else?

No response