I have noticed that it takes a while to "select all", open pages, move text boxes around my pages. It also crashes quite a bit. I just upgraded the RAM on my iMac and it is still extremely slow. Hoping someone can help. Thank you
Apologies to find you on this issue.
It might also happen because of preferences.
Please try the following steps see if any of them works.
Solution 1: Reset Preferences
Now try to launch Muse and check if it works
Solutions 2: Uninstall and Reinstall
Uninstall Muse from Creative Cloud application
During the process please click "Yes Remove Preferences"
Once Muse is uninstalled and reinstall it and try to launch.