In what appears to be a recent and spontaneous change, teh Ubuntu box I use to run our PVR has stopped mounting USB keys rw. THis is on Ubuntu -- when Ifirst noticed the problem I was still running 13.10, but am now updated to 14.10. WHen I plug in a key, it will sometimes (but not always!) appear to mount as usul to /media/matt/something , opening up a nautilus window. but any attempt to write to the disk will fail due to lack of write permission. Attempts to remount also fail: ~$ sudo mount -o rw,remount /media/matt/Linux\ Mint\ 17\ Xfce\ 32-bit/ mount: cannot remount /dev/sdb1 read-write, is write-protected Meanwhile, dmesg says this, which I don't entirely understnad: 794.736021] usb 1-6: new high-speed USB device number 4 using ehci-pci [ 794.869458] usb 1-6: New USB device found, idVendor=1221, idProduct=3234 [ 794.869463] usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 794.869466] usb 1-6: Product: Flash Disk [ 794.869469] usb 1-6: Manufacturer: USB2.0 [ 794.869471] usb 1-6: SerialNumber: 100000000000068B [ 794.869731] usb-storage 1-6:1.0: USB Mass Storage device detected [ 794.872208] scsi7 : usb-storage 1-6:1.0 [ 795.874368] scsi 7:0:0:0: Direct-Access USB2.0 Flash Disk 2.50 PQ: 0 ANSI: 2 [ 795.874586] sd 7:0:0:0: Attached scsi generic sg2 type 0 [ 795.875227] sd 7:0:0:0: [sdb] 2068480 512-byte logical blocks: (1.05 GB/1010 MiB) [ 795.876225] sd 7:0:0:0: [sdb] Write Protect is off [ 795.876228] sd 7:0:0:0: [sdb] Mode Sense: 0b 00 00 08 [ 795.877226] sd 7:0:0:0: [sdb] No Caching mode page found [ 795.877229] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 795.882222] sd 7:0:0:0: [sdb] No Caching mode page found [ 795.882226] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 795.882860] sdb: sdb1 [ 795.882863] sdb: p1 size 2445312 extends beyond EOD, enabling native capacity [ 795.885227] sd 7:0:0:0: [sdb] No Caching mode page found [ 795.885229] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 795.885858] sdb: sdb1 [ 795.885861] sdb: p1 size 2445312 extends beyond EOD, truncated [ 795.891228] sd 7:0:0:0: [sdb] No Caching mode page found [ 795.891233] sd 7:0:0:0: [sdb] Assuming drive cache: write through [ 795.891235] sd 7:0:0:0: [sdb] Attached SCSI removable disk [ 796.069733] ISO 9660 Extensions: Microsoft Joliet Level 3 [ 796.070732] ISO 9660 Extensions: RRIP_1991A ----- this happens with all usb keys, all of which I am able to mount on my laptop, which runs arch linux. Any htoughts on how to proceed? Thanks as always, Matt