Q:

Cannot increase Samples past 1

In my quest to improve rendering times with Cycles I managed to break my file (I think).
Now, when I enter (or slide the cursor) an e.g. 12 value in the Samples box, I get the following message:
bpy.context.scene.cycles.samples = 1
Can't edit driven number value, see graph editor for the driver setup.
Choosing a preset from Sampling Presets doesn't reset the sample value.
I've even tried to open the Python console and set it from there, but it still doesn't change the UI, nor the actual render.
Consequently nothing (visible) renders with a sample of 1.
Any pointers on how to revert my rendering samples much appreciated.

A:

Remove Drivers
You may have somehow added a driver to that value (e.g typing #frame in the field).

Drivers can use properties, numbers, transformations, and scripts, to control the values of properties.

By assinging a driver to the Samples quantity, you are basically telling Blender to pick the value from somwhere else (e.g. scripted expressions,...).The manual inputs will be overrided till the driver is present.

To delete a driver, right click on the field and choose the option from the pop-up menù.

