From Apple: The 10.5.1 Update is recommended for all users running Mac OS X Leopard and includes general operating system fixes that enhance the stability, compatibility and security of your Mac. For detailed information on this update, please visit this website: http://docs.info.apple.com/article.html?artnum=306907. For detailed information on security updates, please visit this website: http://docs.info.apple.com/article.html?artnum=61798. The following improvements for both PowerPC and Intel-based Macs are included in this update
AirPort
Allows password-protected accounts on AirPort Disks to show up on in the Finder’s Shared Sidebar. Resolves an issue with saved passwords for wireless networks.
Back to My Mac
Improves the reliability of Back to My Mac-enabled Macs appearing in the Finder’s Shared Sidebar. Improves compatibility with D-Link NAT gateways.
Disk utilities
Restores the functionality of the progress bar during permission repairs in Disk Utility. Addresses an issue that could produce an alert when creating disk images using Disk Utility or Terminal. Improves disk partitioning when multiple RAID sets are created on the same disk.
iCal
iCal alarms are now more reliably delivered via email. Resolves an issue when inviting attendees via a CalDAV account.
Improves stability when resizing columns in the message viewer or switching between Stationery templates in email messages. Addresses an issue in which attachments enclosed inside an HTML link may not be clickable in email messages. Fixes an issue with email accounts added using the “Simple Setup” feature in which messages cannot be sent due to an SMTP connection failure. Improves Smart Mailboxes compatibility with .Mac Sync, and addresses an issue with To Do’s disappearing when using Smart Mailboxes. Resolves an issue with syncing Mail accounts with .Mac in which multiple On My Mac folders appear in the Mailbox pane.
Networking
Addresses an issue in which Microsoft Windows shared folders may be read-only when connected via SMB.
Printing
Resolves an issue in which user-selected values on Paper Feed PDE are reset to default while saving a custom preset.
Security, Firewall
Addresses a code signing issue; third-party applications can now run when included in the Application Firewall or when whitelisted in Parental Controls. In Security preferences’ Firewall tab, the “Block All” option is now called “Allow Only essential services” Includes recent Apple security updates.
System and Finder
Addresses a potential data loss issue when moving files across partitions in the Finder. Resolves an issue with login after turning off FileVault for a specific user account. Improves compatibility with Adobe Flash-based uploaders used by .Mac Web Gallery and certain other websites and applications. Resolves a potential text drawing issue with certain Adobe Flash-based websites and applications.
Time Machine
Addresses formatting issues with certain drives used with Time Machine (specifically, single-partition MBR drives greater than 512 GB in size as well as NTFS drives of any size and partition scheme). Resolves an issue in which files restored in Time Machine may be restored to the backup hierarchy rather than the folders to which they belong.
