can't add or remove tiles from start

Hi there,
I have a Surface Pro3 which came with win10 installed (unlike my other SP3 which I upgraded to W10). I just decided to customize my start menu a bit with some live tiles re-arrangement.
Problem: I can't seem to pin or unpin apps to the tiles section of the start menu. When I right-click (or touch-hold) and select "pin to start" it shows as pinned (in that the option then becomes to unpin) but the tile never shows up with the other tiles.
Likewise, I can't remove any tiles that are already there.

Somehow the tiles seem to have become locked.

Any help? :)
Thanks!
Kieran

Bump!

Pretty please? I'm pretty stumped on this....
Thanks for any guesses as to what's going on!

Run a system file check to look for corrupt files. It will try to do repair if any found.

Right click at Start button > click Command Prompt (Admin) > at the flashing prompt, copy/paste this.......
sfc /scannow

> press Enter.
It will take quite sometime.
When finished, it will give you one of the 3 reports...............(paraphrasing)
1. No integrity violation.
2. Found corrupt files and repair successful.
3. Found corrupt files but unable to repair.

If the report is #1, your solution lies elsewhere.
If the report is #2, check if your problems have been resolved.
If the report is #3, use this method................
In the same Command Prompt (Admin) windows, copy and paste this command...........

dism /online /cleanup-image /restorehealth

> press Enter.
Again it will take some time.
When finished, it will give you a report.