help with DPP4 unable to open file

have downloaded and saved a number of folders to computer, i am unable to open one folder in DPP4. i just get a small view of file with a pencil and a circle with line through it(like no entry sign) and unable to do anything with it. this only happens with one folder all other folders i have downloaded are ok. what have i done wrong and can i rectify it. many thanks Skully. P.S. Mac OSX

What camera was used for shooting the photos in the folder? Most cameras are now supported by DPP4 but there are still a few that aren't supported. You will need DPP3 in order to process the photos from these cameras.

DPP4 can open JPG files from any camera. It is the CR2 files from some older bodies that must be opened with DPP3.

Sometimes one corrupt file disables the entire folder.

I'd create a new folder and copy the files into it one by one (or in small batches), checking the new folder's soundness after each added file (batch).

thanks for the replies everyone. Camera is an 80d, just upgraded from 450d was using Elements 11 and found out could not open files any longer so that is why i tried DPP4. have downloaded trial version of Elements 2018 and this works ok. tried copying files into another folder and files still unable to open in DPP4. DPP4 is ok with files from other folders both Jpeg and Cr2, all taken with same camera. i will have to upgrade to Elements 2018 but would still like to find answer to my problem as i don't want to be beaten. Skully.

Download the latest version of DPP, it will certainly open 80D RAW files.

updated my version ofDPP4 and files now open, looked at information and found that they were taken with 450d and not 80d as i thought, my mistake. would like to thank all who helped me. . note to self do not be so forgetful in future .

Somehow familiar ...