So the issue is this:

I've installed sshfs on Ubuntu 12.04 and I'm trying to connect to a couple of remote servers. So initially the mount seams successful. Sometimes Gnome even picks it up and displays the "new device found" box at the bottom of the screen. but from here on there is not much that works. Or at least not any more. The first couple of times i connected it seamed to work fine, and I was able to transfer some files, then i disconnected using fusermount -u <folder> and after reconnecting a little later the trouble started. Now after executing sshfs -o ServerAliveInterval=15 -o reconnect -C -o workaround=all -o idmap=user root@<host>:/ <folder>, when I change directory into the mount-point, the shell just freezes. Strangely ls -al <folder> works when listing just the root of the remote system, but nothing more. Also every file-explorer I've tried freezes just like cd <folder>.

To me it seamed like there was some kind of zombie thread or something hanging around my system, due to the fact that it did work the first time, so I have tried rebooting but no luck.

sshfs -V gives this:

SSHFS version 2.3
FUSE library version: 2.8.6
fusermount version: 2.8.6
using FUSE kernel interface version 7.12

So yea, any ideas?