Playback will not work in MS4

First time creating a new project everything works fine, but when saving and reopening the file, it opens and starts loading the sound libraries, but the mixer doesn't load anything and instead is left blank. what playback is started, the playback bar stays at the start of bar 1, not moving or playing any sound. there is no option to change plugins in this state. I have tried everything in my power, but nothing works. I made a previous post in the forum as well to no reply https://musescore.org/en/node/340702 . I don't know why this is happening but it is VERY frustrating. Is there any way to solve this issue?