Corrupt project files (flp's) are a pretty common occurance with FL Studio, especially its older version. When a project file becomes corrupt, it gives you an error message that looks something like this;
Access violation at address…
Fortunately, this is a pretty easy problem to fix with one of FL Studio's hidden features.
The first thing to try is to check if you have any auto saved backups of the project. You can find these by going to the following path:
If you can't find it, don't worry. FL Studio has its own "diagnostic tool" to use for this problem. You can download it by clicking here.
It looks something like this:
When opening it up, the first thing to do is to choose "Fix FL Studio song project" and load your corrupt project file into the browse tab. This will give you two options:
Choose the first option first. This will automatically find the plugins that causes the crash, and you will be able to save a new version of the project without the crashing plugin automatically.
If this doesn't work, choose the second option. To fix the project with this option, you have to go through a whole list of plugins and save new versions of the project file one by one without plugins that may cause the crash. It may take a while, but if the project is big you may want to put down the work to recover it.
I hope this helped you. Cheers.