Thank you very much for welcoming 
I’m maybe blind, but I couldn’t find any button for sending a message. Neither in my mailbox nor in your profile. But it’s ok to post it here I think.
I took the only file with an error, all other files (10 in total) have warnings and / or infos only.
15:06:00.656 [main] INFO org.cryptomator.launcher.Cryptomator - Starting Cryptomator 1.5.15 on Mac OS X 10.16 (x86_64)
15:06:01.626 [JavaFX Application Thread] INFO o.c.ui.launcher.FxApplicationStarter - JavaFX Runtime started.
15:06:50.232 [JavaFX Application Thread] INFO o.cryptomator.ui.fxapp.UpdateChecker - Current version: 1.5.15, lastest version: 1.5.15
15:07:05.954 [App Scheduled Executor 01] INFO o.c.common.settings.SettingsProvider - Settings saved to /Users/xxxxxx/Library/Application Support/Cryptomator/settings.json
15:07:17.409 [JavaFX Application Thread] ERROR o.c.u.a.ChooseExistingVaultController - Failed to open existing vault.
java.nio.file.NoSuchFileException: /Volumes/WD20TB/_Verwaltung/CM_cache/DLGnochSortieren: Not a vault directory
at org.cryptomator.common.vaults.VaultListManager.add(VaultListManager.java:57)
at org.cryptomator.ui.addvaultwizard.ChooseExistingVaultController.chooseFileAndNext(ChooseExistingVaultController.java:81)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:76)
at jdk.internal.reflect.GeneratedMethodAccessor38.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:273)
at com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:83)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1859)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1729)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8889)
at javafx.scene.control.Button.fire(Button.java:203)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:208)
at com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:247)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:234)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3856)
at javafx.scene.Scene.processMouseEvent(Scene.java:1851)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2584)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:409)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:299)
at java.base/java.security.AccessController.doPrivileged(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:447)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:412)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:446)
at com.sun.glass.ui.View.handleMouseEvent(View.java:556)
at com.sun.glass.ui.View.notifyMouse(View.java:942)
at com.sun.glass.ui.mac.MacView.notifyMouse(MacView.java:127)
15:09:41.079 [App Background Thread 004] INFO o.c.u.a.CreateNewVaultPasswordController - Created vault at /Volumes/WD20TB/_Verwaltung/CM_cache/DLGnochSortieren
15:09:42.275 [App Scheduled Executor 01] INFO o.c.common.settings.SettingsProvider - Settings saved to /Users/xxxxxx/Library/Application Support/Cryptomator/settings.json
15:09:44.046 [JavaFX Application Thread] INFO o.c.u.r.RecoveryKeyDisplayController - Recovery key copied to clipboard.
15:10:12.897 [App Background Thread 005] INFO org.cryptomator.common.vaults.Vault - Storing file name length limit of 220
15:10:13.180 [App Background Thread 005] INFO o.c.frontend.webdav.WebDavServer - Binding server socket to localhost:4xxx7
15:10:13.188 [App Background Thread 005] INFO o.e.jetty.server.AbstractConnector - Started ServerConnector@4fa9dc33{HTTP/1.1, (http/1.1)}{localhost:4xxx7}
15:10:13.190 [App Background Thread 005] INFO org.eclipse.jetty.server.Server - jetty-10.0.1; built: 2021-02-19T18:44:52.951Z; git: d0bfd9145ddac13b73xxxxxxxxfcbf4a48132397; jvm 16+36
15:10:13.212 [App Background Thread 005] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.s.ServletContextHandler@15914423{/,null,AVAILABLE}
15:10:13.221 [App Background Thread 005] INFO org.eclipse.jetty.server.Server - Started Server@2ac87cc1{STARTING}[10.0.1,sto=0] @253151ms
15:10:13.221 [App Background Thread 005] INFO o.c.frontend.webdav.WebDavServer - WebDavServer started.
15:10:13.245 [App Background Thread 005] INFO o.e.j.s.s.DefaultSessionIdManager - Session workerName=node0
15:10:13.248 [App Background Thread 005] INFO o.a.j.w.server.AbstractWebdavServlet - authenticate-header = Basic realm="Jackrabbit Webdav Server"
15:10:13.248 [App Background Thread 005] INFO o.a.j.w.server.AbstractWebdavServlet - csrf-protection = null
15:10:13.248 [App Background Thread 005] INFO o.a.j.w.server.AbstractWebdavServlet - createAbsoluteURI = true
15:10:13.248 [App Background Thread 005] INFO o.e.j.server.handler.ContextHandler - Started o.e.j.s.ServletContextHandler@5648f151{/wg-qe5aTTcgM/DLGnochSortieren,null,AVAILABLE}
15:10:13.249 [App Background Thread 005] INFO o.c.f.w.s.WebDavServletController - WebDavServlet started: /wg-qe5aTTcgM/DLGnochSortieren
15:10:13.667 [App Background Thread 005] INFO o.c.f.w.s.WebDavServletController - Mounting http://localhost:4xxx7/wg-qe5aTTcgM/DLGnochSortieren using org.cryptomator.frontend.webdav.mount.MacAppleScriptMounter
15:10:13.899 [App Scheduled Executor 02] INFO o.c.common.settings.SettingsProvider - Settings saved to /Users/xxxxxx/Library/Application Support/Cryptomator/settings.json
15:10:14.032 [JavaFX Application Thread] INFO o.c.ui.unlock.UnlockWorkflow - Unlock of 'DLGnochSortieren' succeeded.
15:10:18.158 [App Scheduled Executor 01] INFO o.c.common.settings.SettingsProvider - Settings saved to /Users/xxxxxx/Library/Application Support/Cryptomator/settings.json
17:29:32.209 [webdav-905] WARN org.eclipse.jetty.server.HttpChannel - handleException /wg-qe5aTTcgM/DLGnochSortieren/AH/Art_Unknown_1080p.mp4 java.io.IOException: java.util.concurrent.TimeoutException: Idle timeout expired: 30001/30000 ms
18:00:56.682 [webdav-1216] WARN org.eclipse.jetty.server.HttpChannel - handleException /wg-qe5aTTcgM/DLGnochSortieren/AT/Flex%20-%20Trainer02.mp4 java.io.IOException: java.util.concurrent.TimeoutException: Idle timeout expired: 30005/30000 ms
18:16:46.780 [webdav-1358] WARN org.eclipse.jetty.server.HttpChannel - handleException /wg-qe5aTTcgM/DLGnochSortieren/AT/Liz2407.mp4 java.io.IOException: java.util.concurrent.TimeoutException: Idle timeout expired: 30002/30000 ms
19:10:24.383 [webdav-1564] WARN org.eclipse.jetty.server.HttpChannel - handleException /wg-qe5aTTcgM/DLGnochSortieren/AT/Flex%20-%20Trainer08.mp4 java.nio.channels.AsynchronousCloseException
19:16:09.453 [App Background Thread 006] INFO o.e.j.server.handler.ContextHandler - Stopped o.e.j.s.ServletContextHandler@5648f151{/wg-qe5aTTcgM/DLGnochSortieren,null,STOPPED}
19:16:09.454 [App Background Thread 006] INFO o.c.f.w.s.WebDavServletController - WebDavServlet stopped: /wg-qe5aTTcgM/DLGnochSortieren
19:16:09.454 [App Background Thread 006] INFO org.cryptomator.common.vaults.Vault - Unmounted vault 'DLGnochSortieren'
19:16:09.456 [JavaFX Application Thread] INFO org.cryptomator.ui.lock.LockWorkflow - Lock of DLGnochSortieren succeeded.
19:16:13.264 [main] INFO org.cryptomator.launcher.Cryptomator - UI shut down
I started to copy everything with the finder. Just after I realized something went wrong with the files, I decided for TeraCopy, simply for the reason to compare the checksums automatically.
If I create a new vault, same behavior. The file itself also has no influence on the effect. As some files are correct after the first try, some are correct after I delete them in the vault and copy them a second time, some need to be deleted and copied again several times. In the end of the day every file arrives correct after a random amount of tries to copy them.
The only thing which seems pretty sure, that it happens to large files only. Since several hours it’s running with pictures and documents, already 480’000 files (437GB) finished without a single error. This task runs probably until tomorrow, then I’ll see the total result.
As nobody of you knows this problem, is it possible in theory that other background processes can cause this behavior? If yes, on what kind of process I should have a look?