Some applications are designed to work with one user account at a time. If such an application is already open for one user, and you switch to a different account (for example, with Fast User Switching) you can't open the same application again.
When you try to open an application that is already open in a first user account, nothing happens if you click the application's icon in the Dock. If you open the application by double-clicking its icon in the Finder, a message containing "error -1026" may appear.
As a workaround, quit the application in the first account before opening it in a second account.
Contact the application's publisher for more information or further assistance. Because some applications are designed to be used by one account at a time, this may be considered normal behavior by the application's publisher.
Examples of Apple applications that you can't open by more than one user account at a time
- Final Cut Pro
- Final Cut Express
- DVD Studio Pro
- LiveType
- Cinema Tools
- Compressor
- Shake
- Soundtrack (Mac OS X 10.3 only)
- Logic Audio
- iDVD
- iTunes (Mac OS X 10.3 only)
- Backup 2.0 or earlier (.Mac)
Examples of Apple applications that you can open within multiple accounts
- iTunes (Mac OS X 10.4 or later)
- Soundtrack (Mac OS X 10.4 or later)
- iPhoto
- iMovie
Note: iMovie can't control an attached camera if the camera is already in use by iMovie or another application in a different user account.
- iSync
- iCal
- Keynote
- AppleWorks
- Safari
- iChat
Note: iChat logs out the currently signed-in ID before switching to the other user because you can't have two different iChat accounts signed in at the same time from the same computer.
Related documents
93419:
iTunes: Importing Songs From a CD and Fast User Switching
93495:
iMovie: Fast User Switching and DV Camera Control
25611:
Mac OS X 10.3, Palm HotSync: Fast User Switching - One Mac OS X User May Sync at a Time
25556:
Mac OS X 10.3: Troubleshooting Classic Startup With Fast User Switching