It doesn't seem to have anything to do with activation. I actived before I tried to reinstall, but not work.
Last night I just left it there. One night later, the project was loaded successfully and work well.
The newly created project can be loaded quickly. But history projects takes a long time (one night) to load, even a very small project(only 30s music and only a Alicias Keys in kontakt 6)
I found the CPU has been busy (20% by cakewalk) during loading. It continues until the end of loading.
The strange thing has never happened before.
I reinstalled all historical versions of cakewalk, Even the previous Sonar Platinum(23.10.0.14), but were not working for history projects like this.