Your memory is faulty, I said no such thing in that thread.
https://forums.macrumors.com/posts/20873838/
Point taken, although both times you've presented this problem, you've said nothing would indicate that the drive went bad or that you did any investigation.
Saying that the free space on the drive decreased is diagnostically
completely irrelevant. Surely you understand that free space decreases when files are written to the drive and everything is functioning correctly, right?
You could have just as easily reported that the drive
capacity decreased, which
would indicate the flash going bad. The capacity is reported one line above the amount of free space in the drive info window.
The failure you're describing is almost impossible for an SSD.
Blocks of flash can go bad, which is discovered when the drive tries to write to them. The blocks are marked as bad and the drive capacity will decrease. (As soon as all the overprovisioned blocks are used up.)
In this case you would have seen gradually decreasing drive capacity as you try to write to these blocks, not "all of a sudden" 30GB has gone bad.
The only way an SSD could fail such that 30GB is suddenly lost is if an entire chip (or chips) fail, in which case you would lose all the data on that chip. The idea that your computer would still work and you'd still have all your data but it would just be slower makes no sense--you would have had massive data loss.
And what are the odds that a catastrophic failure would ruin almost exactly as much space as you had free, and not a few GB more or less? Astronomical.
So what you are saying happened is basically inconceivable from a technical standpoint, but VERY easily explained by some software going haywire and writing too much data to the drive.
So pray tell, what investigation did you do to make sure this isn't what happened?
