The cold water valve on my bathroom sink stopped working this morning. Hot water works. Every other sink in the house works. Just that one sink is not working with the cold water.

What could cause this?

Do you mean the valve under the sink or the faucet itself is not putting out cold? If it's just the faucet, there's probably trash in the cartridge and isn't letting water flow through.

Depending on the age of the faucet, it could have a valve stem instead of a cartridge, but most likely there's trash in the line in that item.

Turn the water off before you start wrenchin

Or have someone video it for us.

Trash in the faucet cartridge. Turn off the water below the sink and disassemble the faucet. Clear the trash and reassemble.

Okay, back to this again.

First of all, thanks for your tips above. Turns out it was not the faucet cartridge at all, but rather the shutoff valve under the sink. It is one of the newfangled push button valves and I think it is spring loaded. You push the valve to open, and pull to close. I'll push to open it and the sink flows as expected. Come back a few hours later and it has popped back out again and is closed.

Can this valve be adjusted?

No turn to the left and pull it off

Zip tie it down.

I’ve never seen a stop like this..??

Here’s a pic of the valve. I like the zip tie idea, but have to figure out a way to attach it.

Plumbcrazy- it just spins when you turn it.

Use 2 zip ties. On slightly loose on the pipe. Then use a 2nd zip ties run through the first one around the push butto valve to hold it down tightly