Hi there
After upgrading from Pie to R my Samsung Galaxy S5 SM-G900F (klte), the camera refused to store pictures on the SDCard unless the phone was rebooted !
To solve the problem, I had to reformat (after backup) the SDCard.
The SDCard was (and still is) configured to extend the memory (not external SDCard) and the /e/ standard camera application is configured by default to store pictures in /storage/emulated/0/DCIM/OpenCamera. Storage Access Framework option is not set.
As it tooks me some time to fix the problem, I would like to share it with the community.
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