Without any specific info about your documents, the images used, save locations, your system and so on we can't realyl say much. It sounds to me like you bumped into that old issue with placed images not being used correctly, but with so little info it's really near impossible to say what's going on.
Sorry to hear about this experience. As suggested by Mylenium, it would help if you could share a screen recording/screenshot of the problem and the exact version of the OS and Illustrator installed on your computer so we can investigate this further.
Also, kindly check if Illustrator behaves this way with other files as well. If it does, kindly move your files to a location on the internal drive like the desktop and check if it helps.