General tips which might help. Don't use outdated or a different version's mods, try deleting all your old/backup saves (C:\Users\YourPCName\AppData\Roaming\RenPy) this folder has backup saves, try deleting everything and reinstalling, try downloading from another file hosting link, use x32 or x64 executable (whichever is relevant to your system), check if your Anti-virus has deleted some files or not (with VNs, it's a false positive most of the time, so not to worry).
If you're using MAC or Android, sorry I have no clue. Other MAC users can help with the former, and Android porter's should be able to help with the latter (if it's not done by the dev themselves). If it's an issue with the compressed version, the person who compressed the VN should be able to help. Most of the time, Android ports and Compressed versions are provided by users on this site, so dev might not be able to help with issues in those versions.
Whenever you encounter any bugs, an "Error Log" should show up, if you attach that to your comment and provide any other relevant info (ex- system specs, Win/Mac/Android, compressed or uncompressed, any mods or patches installed, etc), that might better help others to identify and solve your problem.