Conflict Resolver is an application used by Apple's sync services. Data can be synced between services like MobileMe

MobileMe

MobileMe was a subscription-based collection of online services and software offered by Apple Inc. Originally launched on January 5, 2000, as iTools, a free collection of Internet-based services for users of Mac OS 9, Apple relaunched it as .Mac on July 17, 2002, when it became a paid subscription...

 and Gmail

Gmail

Gmail is a free, advertising-supported email service provided by Google. Users may access Gmail as secure webmail, as well via POP3 or IMAP protocols. Gmail was launched as an invitation-only beta release on April 1, 2004 and it became available to the general public on February 7, 2007, though...

 to devices like Macs, PCs, and mobile devices. The sync services are utilized by several applications including Address Book, iCal

ICal

iCal is a personal calendar application made by Apple Inc. that runs on the Mac OS X operating system. iCal was the first calendar application for Mac OS X to offer support for multiple calendars and the ability to publish/subscribe calendars to WebDAV server....

, Mail

Mail (application)

Mail is an email program included with Apple Inc.'s Mac OS X operating system. Originally developed by NeXT as NeXTMail, a part of their NeXTSTEP operating system, it was adapted, following Apple's acquisition of NeXT, to become OS X's Mail application.Mail uses the SMTP, POP3, and IMAP protocols,...

. Conflict Resolver is executed in the event that a sync service cannot decide on which version of the data to use, creating a conflict. The user is prompted to choose which version of the data to use (MobileMe or local) and whether the user wishes to apply the same changes to all conflicts or review them individually.

Conflict Resolver resides at:
/System/Library/PrivateFrameworks/SyncServicesUI.framework/Versions/A/Resources/Conflict Resolver.app in versions of Mac OS X

Mac OS X

Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...

 since 10.5. In Mac OS X 10.4, the application was located at /System/Library/CoreServices/Conflict Resolver.app.