Hi i have a strange problem with usb : when i insert a device like pendrive and other nothing happens: mac doesn't recognize usb!
how can i resolve? thank a lot

Did it worked before?

Ensure that you have matching versions of mach_kernel and system.kext.

Non-matching versions can cause problems with USB devices not mounting.

do you have
IOUSBFAMILY.kext
IOUSBMassStorage.kext
?

of course i've also replaced IOUSBFamily.kext but now when i turn on my mac, a window appears and it says that there is a problem with that kext. I've tried to replace the original but nothing happens and i have the same problem. Now my mac can't use usb mice and usb keyboards and also ps/2 mouse and keyboard. I'm desperate! please help me

What kind of problem is OS X saying it is having? if it is simply that the permissions are incorrect then you can boot up via "-s" and perform the following:

/sbin/mount -uw /
cd /System/Library/Extensions/
chmod -R 755 * && chown -R root:wheel *
cd ..
rm -R Extensions.mkext
kextcache -a i386 -e
reboot


this will simply repair the permissions and rekext your Extensions folder for the follow-on boot.

If the problem is not the permissions, let us know...

EDIT: glad you caught that.... "-x -s" should have been what I wrote so you would boot in safe single user mode instead of simply single user mode. Thanks.

---

i've tried to do that but when :/root appears it also appears error: fireware unable to determinate security mode etc.. and it'a impossible to write anything....

what can i do?

EDIT: i've boot in single user mode with -x -s and i've modified the permissions now i can use my mouse and my keyboard! THANKS YOU VERY MUCH