Plasma 5 hangs on Startup (Kubuntu 15.04 beta 2

[CaCO3]

After updating my Kubuntu 15.04 Beta 2 yesterday, Plasma wont start anymore.
After logging in it shows me the screen with the progress bar, where it gets stuck at around 60%.
I know it continues loading in the background but the start screen never disapears.

After a while I hear the startup sound and see notifications, i.e. from yakuake.
Also I am able to press ctrl-alt-bksp to kill the session.

When starting with another user, it starts correctly.

[CaCO3 (caco3)]

As I could figure out till now is that one or more files in my home are blocking the start.
I am still in the process of figuring out which one it is.

[CaCO3 (caco3)]

OK, I was able to trace down the issue.
It happened that there is an empty file .config/kglobalshortcutsrc.lock which caused the startup to hang. After removing that file, all is working again.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Charles (cblegare-atl)]

I had this exact same issue and worked around it by deleting a .lock file (not the same one but also in ~/.config)

[cs224 (cs224)]

I just had this exact same problem, except that I did not only have one .config/kglobalshortcutsrc.lock file, but a lot of them like:
kglobalshortcutsrc
kglobalshortcutsrc.lock
kglobalshortcutsrc.lock.rmlock
kglobalshortcutsrc.lock.rmlock.rmlock
kglobalshortcutsrc.lock.rmlock.rmlock.rmlock
kglobalshortcutsrc.lock.rmlock.rmlock.rmlock.rmlock
kglobalshortcutsrc.lock.rmlock.rmlock.rmlock.rmlock.rmlock
... and so on ...

After deleting these files I could login again.