How do I open vault located in a read-only directory (Linux)?

I have a vault that is inside a mounted ready-only directory. Without going too much into detail, I can say that I cannot make it not read-only (it’s a snapshot). But that’s not the problem. The problem is that Cryptomator is not able to open that vault. If I try to open it, I see the following error:

Error Code 91OE:CPM8:CPM8
java.nio.file.FileSystemException: /run/user/1000/pika-backup/mount/60d50452/d144ea-98194cfa/media/me/backup/c: Read-only file system
	at java.base/sun.nio.fs.UnixException.translateToIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixFileSystemProvider.createDirectory(Unknown Source)
	at java.base/java.nio.file.Files.createDirectory(Unknown Source)
	at java.base/java.nio.file.Files.createAndCheckIsDirectory(Unknown Source)
	at java.base/java.nio.file.Files.createDirectories(Unknown Source)
	at org.cryptomator.cryptofs@2.7.1/org.cryptomator.cryptofs.common.FileSystemCapabilityChecker.determineSupportedCiphertextFileNameLength(FileSystemCapabilityChecker.java:136)
	at org.cryptomator.cryptofs@2.7.1/org.cryptomator.cryptofs.common.FileSystemCapabilityChecker.determineSupportedCiphertextFileNameLength(FileSystemCapabilityChecker.java:113)
	at org.cryptomator.desktop@1.14.2/org.cryptomator.common.vaults.Vault.createCryptoFileSystem(Vault.java:120)
	at org.cryptomator.desktop@1.14.2/org.cryptomator.common.vaults.Vault.unlock(Vault.java:158)
	at org.cryptomator.desktop@1.14.2/org.cryptomator.ui.keyloading.KeyLoadingStrategy.use(KeyLoadingStrategy.java:79)
	at org.cryptomator.desktop@1.14.2/org.cryptomator.ui.unlock.UnlockWorkflow.call(UnlockWorkflow.java:76)
	at org.cryptomator.desktop@1.14.2/org.cryptomator.ui.unlock.UnlockWorkflow.call(UnlockWorkflow.java:34)
	at javafx.graphics@22.0.2/javafx.concurrent.Task$TaskCallable.call(Unknown Source)
	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$Completion.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)

So before I open an issue, I thought I ask first. Maybe I missed something.

I am using Cryptomator Desktop 1.14.2 on Linux (Ubuntu 24.10), the Flatpak version.

Hi,

My research shows that cryptomator requires the ability to create files that are temporary and you can’t do that obviously in a read-only file system so I don’t think there is any way for you to mount a vault that is on a read-only snapshot.

As far as i know there is no issue for this. And from my point of view, your question is legit. So open away :wink: