Garageband system overload

Hello. I have a late 2014 Mac mini 2,6 GHz Dual-Core Intel Core i5, 8 GB 1600 MHz DDR3 Ram and Intel Iris 1536 MB GPU. In garageband i have been working on a song. It is just 1 minute long and I am starting to get the ,,System overload the audio engine was not able to process all required data in time. This happens after the last bit of the song.After I press ok the rainbow wheel starts showing up and the Mac mini is unresponsive. Either I have to force shutdown the Mac or open a new window and force quit garageband. By the way if you are wondering I just upgraded to a fast SSD over the old HDD and my computer is blazing fast. Could you please help? Thanks for your efforts.