When i see objects that i want to pick up or interact with i have to press "I" to open the invent, then close
the invent, then I can interact with any objects around me.

Surely it should not work like that ?

So left-click isn't working unless you do that?

That's right.

This is nothing to do with what the manual says, I know what the manual says.

Action Key
Left mouse button
As soon as you have something in view and the name/label of a person, an enemy or an item appears, then you can interact with it. Press the action key to perform the desired action, for example speaking with someone, picking up an object, opening a door, laying in bed, frying meat over a fire, striking or blocking in combat, etc.

My problem is that anything I can interact with have no labels and the left mouse button does nothing, if I
press "I" to bring up the inventory then close it, the labels of objects/items appear and then I can use the left mouse button to interact with labeled objects.

Sorry it was me all the time :/ Totaly not concentrating on what I was doing.

When this was happening IE: No item labels no interaction I was running around in combat mode, and pressing the "I" was having the effect of turning off combat mode. I was locked into the fact that on entering a fight you have to press the center mouse button to enter combat mode, but when you finish the fight you have to, press the center mouse again to turn combat OFF. I did not notice the characters stance and assumed that once combat finished you automatically leave combat mode.

So it was down to me assuming something that had to be done manually, sorry to have been a nuisance with this.