Dominik,
any idea about my the long time for starting PM?
If I had to guess, I expect that one or more of your mounted drives (internal, external, or network) had gone into sleep mode and took time to spin up. PM queries all attached drives on startup. Each sleeping drive will take several seconds 5-10 to spin up and return their root folder information. The drives are accessed serially, so if you have three drives that are asleep then you can expect the delay to be up to 30 seconds long.
But that's a hunch. I cannot tell for certain in your video what the cause would be. Another cause would be a very large disk cache that was not emptied on quit (PM has to reconnect with the disk cache on startup.)
-Kirk