Hello I also had the same problem, until today I could fix it with the help of the department of Samsung Customer Service.
Through Chat, they were showing me the steps: (Do not worry that in any case the Gallery content is lost)
1º- Login Settings / Application Manager / All.
2º- Select "Gallery"
.3º- Press "Delete Data"
.4º- Back to the main menu and enter again in "Gallery"
"He came out the same message"
Then I was told to come back into
1º- Settings / Application Manager / All. . .
2º- Select SNS. . .
3º- Press "Delete Data". . .
.4º- Back to the main menu and enter again in "Gallery" He came out the same message"
And finally I was told to repeat the process to select SNS and press "Force Stop" and then "Disable".
I hope I've helped. A greeting.