Canon r6 not saving properly

[bcphoto24]

Has anyone else had the issues of the R6 not saving photos to SD card? I have two photo sessions back to back. I went to upload onto my computer with SD card and all of my pictures from the first session were not there. I put the card back in my camera and they were not there also. All of my pictures from the second session were there tho. I did recover my SD card but they do not seem to be there either. Any ideas or help is appreciated! 

[Waddizzle]

Check both SD cards.  When you remove an SD card and close the door, the camera may automatically switch to saving to the other SD card slot, instead of the now empty slot that you were using.

[Tronhard]

You could check the configuration for how your camera is actually saving to SD cards, given the camera has two cards and can save in multiple configurations.  Did you set this up before shooting?

[TripleL]

I just had this same thing happen.  Photographed an event for more than an hour. I was able to see the images on the back of the camera as I was photographing - all appeared normal.  When I attempted to upload to the computer from the SD card, no photos were visible. (Photos prior to the event are all intact on the SD card; photos taken since are all intact.) No images from that event are viewable on the camera either, however, all others are.  Any help, advice, or suggestions is welcome. Is this an R6 problem? 

[Tronhard]

It's very puzzling, so I hope you will tolerate more questions...
What kinds of cards are you using?   In particular are you using Full-size or micro-SD cards with an adapter?

[TripleL]

I am using a full-size SD card.  I only had one card in the camera at the time. I plugged the SD card into a card reader, then to the USB port on my computer. 

[Tronhard]

Thanks for this information.  Well, second question then...
How do you normally clear space in the card after shooting?
1. Delete individual files as required
2. Select all files and delete them
3. Format the card in the computer
4. Format the card in the camera