@txu your issue may be based on the survey flow logic you have used.  If you put elements (e.g., branch) between blocks you lose the ability to use the back button. Refer to this previous post which  will explain further:  This is unfortunately a limitation of platform.

https://community.qualtrics.com/XMcommunity/discussion/18331/back-button-on-blocks

@ScottG Thanks for the reply. I am aware of the limitation you mentioned. I guess my question was not clear enough. I have the back option available. I am trying to keep participants from changing answers when they go back to previous pages.

@txu ahh sorry; totally didn’t get that when I first read the question, but re-reading it I now see that.  Unfortunately I am not aware of an option to do this myself.