There may be times when you start up your system that the trash will have a folder called "Recovered Files" in it, and it may contain a number of oddly named files that might contain garbled data or could be 0KB in size.
The Recovered Files folder contains temporary files that were used by applications and system processes, which were not properly released and discarded when the application was terminated. This can happen if a program unexpectedly quits, or more commonly if the system crashes in the middle of your work.
The next time the system boots after a crash, it will gather these temporary files and save them in the "Recovered Files" folder instead of immediately deleting them. This provides you with the opportunity to recover data in the rare case that something vital may have been stored in one of these files, though for most home and office applications these files will likely not contain any usable information.
If the "Recovered Files" folder keeps appearing in the trash when you restart your system, it is likely applications are quitting unexpectedly when they are being closed for shutdown. While the culprits could be any system process, it is more likely they are menu extras, system monitors, antivirus scanners, and other third-party utilities you may have installed.
Sometimes this can happen after a system upgrade or other system configuration change, if the utility in question is not fully compatible with the changes.
You can troubleshoot this problem by first running aon the system to clear caches and ensure system components are properly accessible. Then try manually quitting or disabling as many of the running utilities in your system as possible before restarting, and finally be sure to fully update the utilities you have installed, to ensure they are as bug-free and as compatible with your OS as possible.