Apple OS X 10.4 Tiger, lost access to network server drive
Q: I recently upgraded to Apple OS X Tiger 10.4 and now I can't access some of my network server drives.
A: Your user security Keychain file may have become corrupted or become incompatible.
1) From the Applications > Utilities folder, run the Keychain Access utility program.
2) You will see a list of programs, websites, and servers that may have asked you for a password. This procedure may result in these being deleted which will require that you enter your previously saved password again to access the service.
3) From the Keychain Access menu, select Keychain First Aid. Run the repair procedure to see if this fixes the problem.
4) If the problem isn't fixed with Keychain First Aid, then delete all keychain information. You will find a "Delete Keychain" option under the file menu.
Note: Perform all the above at your own risk.