I doubt very much that there's a fix, but here goes:
Ever since I got my first Sony handset, Xperia Miro, I've had random restarts that delete the content of my music playlists, hours spent assembling playlists gone, this is an issue with the Z3C and XA1 too, and there's no way to back up the data.
The XA1 is the only handset of any brand I've had that randomly decides that my WiFi isn't there, it just tells me that there's no signal and refuses to sign in, even though my home router is clearly visible in the list. A temporary fix is to switch airplane mode on and then off, but a full restart is required roughly once per month.
I feel slightly ripped off, largely thanks to Vodafone charging me extra when they claimed to be price matching, refusing to exchange the previous handset after 30 days, reception fault, no network signal, plus the two faults above, they couldn't fix it, so after 2 weeks I got a new, slightly less faulty, handset.
Really, this stuff should have been sorted out before release, it's not like it's much different from the Z3C, just bigger. I've seriously considered getting my old handset repaired, because it was better, faster and more compact.
