projects

Hi all,
have just started using a Zoom R16, so apologies for the basic level of the question;
The documentation seems to suggest that projects save onto the SD card automatically, and that the last project worked on opens up automatically when the device is turned on.
I’ve just turned on to find the one and only project has been deleted
Strange, because I turned on last night, and it was there, no problem.
Could this be an SD card problem?
thank you help