A number of people are having a problem where the Finder will hang or crash, followed by a Finder error message saying "The application Finder.app can't be opened. -10810." The general agreement among affected users seems to be that this is spurred mainly when accessing external drives, but there could be a few other related reasons.
This seems to happen regardless of how drives are mounted, either through various ports (USB or Firewire) and also for networked drives and shares. For networked volumes, a few users have noticed the problem happens when they've had shares mounted while waking from sleep. In these cases a few people have manually unmounted the shares using the Terminal and have been able to clear the error message. Additionally, some with locally attached external disks have found that powering them off and back on while they are still attached yields similar results.
The problem also seems to be closely associated with faults in the Launch Services feature of OS X, since many times it only happens when people access the "Open With..." contextual menu for files on the external drive. Many crash reports include errors from Launch Services, and a few users such as "wolrah" have posted the output of trying to open the Finder via the Terminal:
"Phoenix:~ wolrah$ open /System/Library/CoreServices/Finder.app/ LSOpenURLsWithRole() failed with error -10810 for the file /System/Library/CoreServ ices/Finder.app."
If you're stuck in the problem, there are a few things you can try without hard-resetting your system (which may lead to additional problems and definitely not fix the current one). For these suggestions, you will need to have access to the Terminal, which might be available through Spotlight if you cannot navigate your filesystem or do not have it in the Dock. Optionally, you can run these commands by logging in remotely using "ssh" from another computer, if you have remote login enabled:
If your drives are attached locally, try powering them down while they're still attached. Listen to them and if there is any reading or writing activity (small grinding or chattering noises) then wait for it to silence before hitting the power. Likewise, unplug ethernet cords and turn off AirPort (via the system menu or the Network system preferences) to cut the connection to networked services.
This can also be done via the Terminal by entering the command "mount" to list the disks and shares the system currently is recognizing. Then find the names of those that are not internal disks and enter the following command for each:
sudo umount -fv DRIVENAME
In this command, put "DRIVENAME" in quotes if the name has spaces in it. Additionally, if you only have one internal hard drive, use the following command to unmount all except for that drive:
sudo umount -Af
Kill Finder and Dock processes
Manually killing the Finder and Dock should relaunch them, so run the following command to reset these applications:
sudo killall Finder Dock
Use Terminal to shutdown/restart
If you need to restart the system, try shutting down using the terminal instead of holding the power button. The following command will do this for the system (you can use "-r" instead of "-h" to restart instead of shutting down).
sudo shutdown -h now
This problem may be something that Apple needs to address in an update, but it definitely seems to be happening to a subset of those running Snow Leopard. It may have been spurred by a faulty setting carried over from Leopard in the upgrade process, but not everyone has mentioned whether or not these problems are on upgraded installations versus clean installs of Snow Leopard. There are a few things you can try to fix this problem:
Rebuild launch services
Since these problems seem associated with the launch services in OS X, my first recommendation would be to clear them by removing the launchservices preference files from your user library and by entering the following command (all one line--copy and paste all lines of the command since the CNET layout is cutting off the last part of it) in the Terminal:
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -seed -rfv -all user, system, local
This can also be done via third party utilities such as OnyX, as I described in a previous article on resetting launch services.
Reapply combo updater
Since OS X 10.6.1 came out, you can apply the full updater for it again to hopefully clear the problem. Unfortunately people who initially applied this patch after seeing this problem in 10.6.0 did not see any improvement, but it's worth a shot. Additionally, use Disk Utility to run a permissions fix on the boot drive.
Put external drives on spotlight's exclude list
Some have suspected the indexing of external drives by Spotlight may be involved in the problem. As such, try preventing the drives from being indexed by adding them to the Spotlight exclude list in the system preferences.
Reinstall OS X
This is the last step to take, but if nothing else works you can either avoid using your external drives or attempt a reinstall of OS X. Snow Leopard will automatically do an archive and install of your system and preserve user settings and data, but will remove the "Previous System" folder that other versions of OS X left behind.