Check your autoplay settings. Control Panel>autoplay
Set it like screenshot below. Save settings.
Unplug and re-plug your phone. Any difference?
Sorry to seem obtuse but small details matter and your first and last statements are somewhat different. Your first statement led me to believe the photos app would not open the photos. Now you say you can't access the internal storage which would point to a file explorer issue. We have to figure out where the process is breaking down. Please follow this flow and answer.
1. You plug in your phone. File explorer recognizes phone and assigns a drive letter to it. YES or NO.
(At this point, you get a message on your phone. You must allow. Only then will the DCIM folder show up under the drive letter. You have to do this each and every time you plug in your phone)
2. If yes, when you double click on the drive letter, will the drive expand so you are able to see DCIM folder YES or NO.
3. If yes, can you double-click the DCIM folder to expand it to show the folders/files inside? YES or NO.
4. If yes, tell me exactly what happens when you double click on one of the files. Any message or error?
If the answer to any of these questions was NO, it would point to a file explorer issue. Yet, you say the photos will open using a third party app. File explorer is used in conjunction with the app so that makes little sense to me. What app and exactly how are you opening the folders?
