Last week, I lifted my MacBook Pro Mid 2012 solely by the front right corner. After that, all operations were incredibly slow and I got lots of spinning color wheels. When I tried to run First Aid on the SSD in Disk Utility, the drive would not even appear in the list of devices. When I checked the SSD's SMART details with ‘smartctl’, there was nothing wrong. Still, I opened up the Mac and swapped out the SSD for a spare known to be working well in another machine. The second SSD also failed to show up in Disk Utility. The hard drive cable appeared to be fine, but after reading the comments here and on other sites, I decided to replace the cable with a new one ordered from ifixit. With the new hard drive cable and the original SSD, my MacBook Pro is now back in business and disk access is fast again. Hooray! Thanks for the very clear instructions. Like the previous poster, I was afraid of damaging the new cable when bending it. I used the flat tip of a spudger to bend the cable.

Thanks Ben. Of course I meant to say "lower burr" above. The beans are oily so that could be a factor. I notice that the grounds are getting a lot of static electricity since I replaced the impeller, and I get grounds clinging all the way up the walls of the plastic output container. The grinder sounds normal, unlike the one in the first video link above. I will try checking the burr state and the flow process as you suggest.

I have the model BCG800CBXL “with dosing IQ” that changes the “dose” depending on the grind fineness setting. Recently, with fixed “number of cups” setting and grind fineness, the amount of coffee output by the grinder has been decreasing. I had a few events where the exit chute got clogged and the motor began to race. And then I found this page; thanks for writing it, Ben! I inspected my impeller and sure enough, the blades were worn down away from the edges of the grinding chamber. I ordered the replacement impeller from Shapeways. A long shafted Craftsman #2 Phillips screwdriver worked for reaching the top cover screws. I cleaned the exit chute. I did not reinstall the felt washer and my upper burr sits a wee bit above where it used to on the spindle, but the impeller fit perfectly with no sanding. The grinder runs as expected after reassembly! But I am still having to select a large number of cups on the front panel to get the desired output amount.