Viele kennen es. Firefox braucht manchmal sehr lange bis es gestartet ist.
Hier die Lösung:

Open Firefox and write in adress bar: about:config.

Search:

- network.http.pipelining and change to "true"
- network.http.proxy.pipelining and change to "true"
- network.http.pipelining.maxrequests and change value to 30 or or else

Now click PPm in white field and select by context menu: new --> integer: change name to nglayout.initialpaint.delay and set value to 0

Reboot your Firefox.