Windows 10: why is there a red cross next to my folder?

I've unsynced my onedrive from my computer as it did not have enough storage. however there is still a red cross next to a folder, when i go into the folder there are no red crosses next to the individual files. why is this happening?

:)

 

Red cross on all pictures in a folder

All the pictures in one of my picture folders have a red cross on them. How do I get rid of the cross?

 

Red cross on all pictures in a folder

Thanks for all this Greg. Much of what you suggest is beyond me but I have been able to solve the problem. Fortunately, I still had the photographs on my camera's SD card so I deleted the folders from my hard drive and from onedrive and downloaded them
again but this time into a new onedrive folder, then copied the folder from onedrive to my hard drive and there are no red crosses. I think that before I saved them to the hard drive first. Anyway, I am grateful for your suggestions which prompted me to
find a solution.

 

Red cross on all pictures in a folder

Thanks for this Greg. I have checked and this folder is not backed up in onedrive. I have noticed that other recent picture folders are also not backed up and they also have the red cross on files (and a double arrow on the folder rather than the green
tick). So do I just copy these folders onto onedrive? Why don't they sync automatically?