Solution on the .:: Visibility Panel ::. GoTo -> Unhide All Button (Yellow Lightbulb) This Restores hidden sub-objects to visibility such as hidden Vertices.
JUST SIMPLY CLICK "B" ON YOUR KEYBOARD!!!!!!!!!!!!! YOUR SOFT SELECTION IS ON!!!!!!!!!
XD
GOOD LUCK!!!!!!!!
When you can't access component-mode (when you're on object-mode and you right-click to get to face, edge or vertex mode), pressing the b key a few times worked for me! Thanks to t burbage!
The thing might be that the layer your object is in is referenced. Just set selected layers to "Normal"
I solved it out by unchecking the "make the selected object live" icon, it is present on that status line , looks like the magnet sign, the last magnet sign on the status line. Yup, I solved it by making that icon off
I had this same issue and realised that I had soft select on. I know this is an old message but just thought I would say in case anyone has the same issue.