They´ve sent me an autorun folder and gave me instructions:
It looks like the solution to your problem is:
1. Downgrade to 2.15.1: MPC 3 Beta | How Do I Roll Back To MPC 2? : Akai Professional
2. Factory content reinstall (Step by step - below)
3. Then upgrade back to MPC 3.
Akai MPC Content Reinstall: MPC Key 61 Autorun
1. Download the .zip file.
2. Unzip the downloaded file.
3. Copy the contents (the “autorun” folder) onto either a USB stick, or an SD card (exFAT format, at least 16GB capacity), and make sure this content is placed in the root directory of the removable device - do NOT place the content inside a folder on the removable drive.
4. Turn on MPC and wait until the Demo selection screen pops up. (If you do not have a project Dialog box after startup, power off the MPC, insert your SD or USB, and power it back on. The MPC will start the import automatically. skip to step 7)
5. Plug in the prepared USB stick or SD card.
6. A pop-up will appear asking if you want to download the contents. Press “YES”.
7. The MPC will reboot to a black screen and will start importing the content. DO NOT POWER OFF THE UNIT.
8. The unit will reboot after it has completed the import, and the content will be available thereafter as normal.
But inside that autorun folder there is an Expansions.tar.gz (zipped loop package). Should I unzip this folder as well?