Disconnect drive fails

When I open my vault (cloud drive), Explorer opens a window with the expected drive letter - fine.
When I just close the vault, the window gets closed and the vault gets locked - fine.
However when I write anything to the drive, and then try to close the vault (no matter if I close the explorer window manually or not) I get “disconnect drive failed”.
After killing the CM process and restarting, everything looks hunky dory, and I find the vault locked OK.
Below is a log file - I can provide a good one as well … (I’d be hapopy to rather attach a file to the post if someone could please explain how to do this here)
Any ideas? BTW using 1.4.15 on Win8.1

18:17:15.377 [main] INFO  org.cryptomator.launcher.Cryptomator - Starting Cryptomator 1.4.15 on Windows 8.1 6.3 (amd64)
18:17:15.475 [main] INFO  o.c.launcher.IpcProtocolImpl - Received launch args: 
18:17:15.681 [JavaFX Application Thread] INFO  org.cryptomator.launcher.Cryptomator - JavaFX application started.
18:17:15.806 [JavaFX Application Thread] INFO  org.cryptomator.jni.JniModule - loaded WinFunctions.dll
18:17:15.846 [JavaFX Application Thread] INFO  o.c.ui.controllers.MainController - Unable to setPreferencesHandler, probably not supported on this OS.
18:17:16.942 [JavaFX Application Thread] INFO  o.c.ui.controllers.WelcomeController - Current version: 1.4.15, lastest version: 1.4.15
18:17:18.706 [JavaFX Application Thread] INFO  o.c.k.WindowsProtectedKeychainAccess - Unable to load existing keychain file, creating new keychain.
18:17:25.970 [Background Thread 2] INFO  com.dokany.java.DokanyDriver - Dokany version: 130
18:17:25.971 [Background Thread 2] INFO  com.dokany.java.DokanyDriver - Dokany driver version: 400
18:18:04.624 [Background Thread 2] INFO  com.dokany.java.DokanyDriver - Unmount and shutdown: E:\
18:18:04.666 [Background Thread 2] WARN  o.cryptomator.frontend.dokany.Mount - Dokany driver for drive E:\: canceled.
18:18:04.669 [JavaFX Application Thread] ERROR org.cryptomator.ui.util.Tasks - Unhandled exception
java.lang.Error: Invalid memory access
	at com.dokany.java.NativeMethods.DokanUnmount(Native Method)
	at com.dokany.java.DokanyDriver.stop(DokanyDriver.java:97)
	at com.dokany.java.DokanyDriver.shutdown(DokanyDriver.java:87)
	at org.cryptomator.frontend.dokany.Mount.close(Mount.java:66)
	at org.cryptomator.ui.model.DokanyVolume.unmount(DokanyVolume.java:99)
	at org.cryptomator.ui.model.Vault.lock(Vault.java:132)
	at org.cryptomator.ui.controllers.UnlockedController.lambda$regularLockVault$1(UnlockedController.java:116)
	at org.cryptomator.ui.util.Tasks.lambda$create$0(Tasks.java:33)
	at org.cryptomator.ui.util.Tasks$TaskImpl.call(Tasks.java:139)
	at javafx.concurrent.Task$TaskCallable.call(Task.java:1425)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)
18:18:10.368 [Background Thread 3] INFO  com.dokany.java.DokanyDriver - Unmount and shutdown: E:\
18:18:10.368 [JavaFX Application Thread] ERROR o.c.u.controllers.UnlockedController - Regular unmount failed.
java.util.concurrent.CancellationException: null
	at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:121)
	at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:205)
	at org.cryptomator.frontend.dokany.Mount.close(Mount.java:67)
	at org.cryptomator.ui.model.DokanyVolume.unmount(DokanyVolume.java:99)
	at org.cryptomator.ui.model.Vault.lock(Vault.java:132)
	at org.cryptomator.ui.controllers.UnlockedController.lambda$regularLockVault$1(UnlockedController.java:116)
	at org.cryptomator.ui.util.Tasks.lambda$create$0(Tasks.java:33)
	at org.cryptomator.ui.util.Tasks$TaskImpl.call(Tasks.java:139)
	at javafx.concurrent.Task$TaskCallable.call(Task.java:1425)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)

This is a known issue. To solve it, please update your Dokany installation to 1.3.0.1000.

Thanks for the quick reply. This did the trick.