Fatal Python error while executing application created in python
Python 3.7 is not supported. After asking relevant questions to OP it is safe to say that they are using an unsupported version of Python when compiling with Pyinstaller.
Alternatives suggested:Wait for support for 3.7 to be introduced in later versions of Pyinstaller.Revert the Python env to 3.6x (Check Pyinstaller website formalist of compatible Python versions first)Ensure that Pyinstaller has not already released a supporting version, in which case you may need to update Pyinstaller instead.
Please follow the link below, the comment suggests you can build the bootloader yourself
Hope this helps,Swift