A couple of days ago JDownloader refused to start any new download.
If I click the start button nothing happens. If I force a download start nothing happens, even the symbol next to the download that I forced to start don't shows either.
Once I've pressed the start button, the stop button doesn't work, if I press stop the start button keeps pressed.
JDownloader is completely silent, don't show any error message.
Doesn't matter from which server I am downloading, nothing works (openload, clicknupload , youtube, etc.)
There is enough free space on the disk. I am running Ubuntu 18.04
I've installed a fresh installation of JDownloader2, but the problem wasn't solved.

12.10.19 10.03.48 <--> 12.10.19 13.21.47 jdlog://3602130900751/

[Jiaz]

Log shows that JDownloader/Java hangs on parsing your fstab/mounts.

at sun.nio.fs.UnixNativeDispatcher.stat0(Native Method)
at sun.nio.fs.UnixNativeDispatcher.stat(UnixNativeDispatcher.java:286)
at sun.nio.fs.UnixFileAttributes.get(UnixFileAttributes.java:70)
at sun.nio.fs.UnixFileStore.devFor(UnixFileStore.java:55)
at sun.nio.fs.UnixFileStore.<init>(UnixFileStore.java:70)
at sun.nio.fs.LinuxFileStore.<init>(LinuxFileStore.java:48)
at sun.nio.fs.LinuxFileSystem.getFileStore(LinuxFileSystem.java:112)
at sun.nio.fs.UnixFileSystem$FileStoreIterator.readNext(UnixFileSystem.java:213)
at sun.nio.fs.UnixFileSystem$FileStoreIterator.hasNext(UnixFileSystem.java:224)

Please check it for invalid/broken entries

The path is correct, the partition is mounted with enough free space, the permissions are rwx. I even tried running JDownloader as sudo, with the same results.
I've straced the running process and there is a system call that I think is causing the hang.
JDowloader is running with PID 23950 and I think is waiting for a process with PID 23975, but I don't have a process with PID 23975. The first syscall after running JDownloader is a futex
and then there are no more syscalls.

futex(0x7fe7b51b99d0, FUTEX_WAIT, 23975, NULL

[Jiaz]

Do you have NFS mounts? with hard mount parameter? see
github.com/elastic/elasticsearch/issues/24361

It has nothing to do with sudo and not connected to JDownloader, Somethings not right with one of your mounted filesystems.

That was the problem, I had one NFS volume mounted, but the server was offline.

Thanks

[Jiaz]

Great! Thanks for the feedback. Glad that we could solve the issue