Symptom
During startup, a dialog box appears with this message:
"The program you are using needs to use a system file that may reduce the security of your computer."
The dialog offers choices of Fix and Use, Use, and Don't Use (Figure 1).
Figure 1 The .kext security warning dialog
Solution
Mac OS X 10.2 and later has stricter security checking of kernel extensions. These files should have permissions that restrict any user other than the system software (the "root" user) from making changes to the file. If a kernel extension has less restrictive privileges, it will trigger this alert.
If you are confident that the kernel extension is the correct, unaltered file, you may click Use to use the file with the existing permissions. Alternatively, click Fix and Use to correct the permissions and use the file.
If you are not confident about the nature of the kernel extension, click Don't Use.
Note: if you select Don't Use, applications and devices that rely on this kernel extension may not function as expected.
In any case, you should contact the vendor of the kernel extension to get a new version that conforms to the expected permissions.