I uploaded a wav file into my audition, spent a lot of time editing down the audio yesterday. I saved the file onto my desktop and opening the file today, the waveform is missing. The entire file is blank. It looks as though I haven't done anything in this file.
Well, you've opened the session, but there are no audio files loaded, so you're looking at an empty session. You need to locate the file you were editing, which may show in the Open Recent list. I should also mention that saving anything on the desktop is not a good idea. Really you should create a folder for your work and save the audio and the session file in it - then you won't run into these difficulties.