My A pillar sunroof drain (driver side) was clogged and I used a weed whacker string to snake down it to unclog it

YES.

Any update on anyone with ideas on how to clean the sunroof drains. I searched and didn't really find anything that worked for anyone. My drivers side front drain is blocked and I had wet drivers side carpets and also dripping from the overhead sunroof button area.
I tried the weedwacker line but that didn't seem to clear anything. I tried from the top and the bottom but it seem to hit a wall somehwere along the line. Any help is appreciated.

Also my car is CPO. Would this be covered for the dealer to take care of? Thanks.

Yes, it should be covered. But the clog is usually at the very bottom at the drain.

In the shop I use air to blow it out, then run some water through to rince out more debris, then blow it out again.

This is worrying the c*ap out of me too, there is so much dust out here, no rain, and when it does rain it rains a mud laden rain due to sands and soil from the sahara, so am worried I will get a blockage too, the compressed air sounds good but can you get adapters that small that can be used in the drain holes?and do you backflush?

I blow from the top down, which isn't easy without pulling the headliner loose if you don't have something to stick in the drain hole fron up top. (I have a hard plastic tube that fits pretty good)

I am having the exact same issue (could be pics of my '03 X5 4.4i) and have cleaned the sunroof drains using some grass trimmer line and air, but could fine no blockage.

When I cleaned up the mess I also found water under the spare and in the bottom of the battery compartment. I checked everywhere else on the X, but nothing was wet. No carpet, liners, sound deadening material, nothing. How is it possible to get so much water ( a good 2+ inches as in the pics) in this location, without anything else getting wet, if it came from the sunroof. This weekend I am going to check the bumper area and see if that is where my issue is. Good luck with yours.

In your case, most likely the rear drains are disconnected or clogged vs the fronts being clogged. I'd peek in the rear of the headliner and see if the drains have come loose. If they're still fully attached I'd park nose up on an incline like a driveway and pour some water in the sunroof channels to see if it is flowing properly or backing up and overflowing out the back of the the sunroof cassette.

If the rear sunroof drains are operating properly and that's not where the water is coming from, it could also be from a leaking body seam under the tail lights... run the hose over the tail lights and see if water comes in from under them. Let us know if you find anything.

Thanks Weasel. I will do this and let you know. I'll post pics if I can find the leak.

J-MAC yes please pics will be great, it is raining cats and dogs out here, more rain than ever, be good to know how to give the holes an annual clean to be safe.