Vault creation on SD card silently fails — no masterkey.cryptomator written

[tobihagemann]

Summary

Vault creation on an external microSD card completes the UI flow but fails to write the vault structure. The vault folder is created on the SD card but contains no masterkey.cryptomator, vault.cryptomator, or d/ directory. The app returns to the empty vault list and briefly shows "File does not exist."

System Setup

• Android: 16 / API36
• Cryptomator: v1.12.3 (3030) Google Play
• Device: Oppo Reno 14 FS G5 (CPH2743)
• Storage: 512 GB microSD card

Cloud Type

Local storage

Steps to Reproduce

1. Open Cryptomator on a device with an external SD card
2. Tap to create a new vault
3. Select "Local storage"
4. Select the SD card
5. Name the vault and proceed
6. Set a password and tap "Done"

Expected Behavior

Vault is created on the SD card with proper structure (masterkey.cryptomator, vault.cryptomator, d/) and appears in the vault list.

Actual Behavior

• App returns to the vault list screen, which remains empty
• The vault folder is created on the SD card but is empty (no vault structure written)
• "File does not exist." error is shown briefly (NoSuchCloudFileException)
• "Add existing vault" workaround fails because there is no masterkey file to select
• UI issues also observed: the FAB/green button is partially cut off, and the keyboard obscures the password field

Reproducibility

Always

Relevant Log Output

I  20260402061830.422  ActivityLifecycle  onResume CreateVaultActivity@296e9a8
I  20260402062013.589  ActivityLifecycle  onResume BrowseFilesActivity@15319f9
I  20260402062120.683  ActivityLifecycle  onResume BrowseFilesActivity@1e2001c
I  20260402062308.985  ActivityLifecycle  onResume BrowseFilesActivity@9b25f7c
I  20260402062604.135  ActivityLifecycle  onResume SetPasswordActivity@1d1ca68
I  20260402063006.119  ActivityLifecycle  onResume SetPasswordActivity@1d1ca68
I  20260402063605.998  ActivityLifecycle  onResume SetPasswordActivity@94d7763
I  20260402063615.330  ActivityLifecycle  onResume VaultListActivity@7c47d3f
W  20260402063615.372  Message  File does not exist.

Anything else?

The vault folder creation (SAF DocumentsContract.createDocument for the directory) succeeds in CreateVault.execute() at line 35. The subsequent cloudRepository.create(vaultFolder, password) call, which writes masterkey.cryptomator via MasterkeyCryptoCloudProvider.create(), fails with NoSuchCloudFileException. This suggests the SAF URI returned for the newly created folder is not usable for child file creation on this device's external SD card implementation.

Reported via support ticket. Awaiting developer confirmation.