Patio door lock
 

One of our doors doesn't lock...the lock doesn't 'catch' so it can lock.

Does anyone else have/had this problem?

This is typically a simple adjustment of the latching mechanism or possibly the need for lubrication of the locking mechanism, do NOT use WD40, use a silicone based lubricant.

Super important
 

I appreciate the insight of your post. There are so many abrasives in our Florida environment that love to latch onto oil and make things worse.

Note that WD-40 is not a single product. It is a brand name for a number of different products, one of which is a silicone based lubricant.

Yep, I just went to Lowe’s found cheap brand old sliding door that matched my latch/lock and replaced the mechanism

Exactly. The ones I've repaired needed replacement, as the latch broke. Good thing is they come with three different size throws, so if you have a supplemental lock, it compensates for the distance.

Would have been an option.

We removed the part of the lock that it latches into out. Behind it, we put a small piece of cardboard and then put the piece back and screwed it in. After that, it worked fine and has been working fine for about 10 years….so that part of the door that is stationery, and slides into is the piece to lock, is the piece we removed. It may not solve your issue but it sounded like the same exact thing as I read through it. Good luck.

We replaced
 

When ours did this, it was the spring that broke. We went to the hardware store and bought a new one. Wasn't expensive and not too difficult to replace.

If lubricating it doesn't work, try that.

I helped my neighbor adjust his last week. You can adjust the two straight head screws (one at the top and one at the bottom) which brings the lock mechanism in closer or out further. I think we just did the top one and it worked after that.

Sliding door lock
 

Mine was the same. I simply shimmed out the latch on the door frame and now it works great!