The calendar files search process
Depending on the selection of the List calendars found into ... radio buttons, iSynCal will look for the calendar files either on the mounted network disks or on the local users' Home folders and disks as described below, hence it will list on the right side popup button all the valid folders found. Please note that a folder containing iCal files is evaluated as "valid" when iSynCal can read its calendar files, thus when the user account running iSynCal, and the account used to mount the network volume when searching inside such a disk, has at least read access for that folder and the enclosed files.
With the introdution of Tiger and iCal 2 both the calendar files format and their location have changed: iCal 1.x used to store its calendar files as plain .ics files into the user's ~/Library/Calendars folder, one .ics file per calendar named as the calendar itself, so that your "Work" calendar would be stored into a file named (you guess it) Work.ics. It was too simple, so Apple decided to complicate our life and iCal 2 now stores its calendars into ~/Library/Application Support/iCal/Sources, where you have for each calendar a folder with a very long name (something like 704A0584-6A68-4EC7-8215-2A06FDF30F29.calendar) where you always find a file named Info.plist and containing some general info about the calendar, e.g. its name, and another file named corestorage.ics, which is used to store the real calendar's data (events, todo, alarms).
Anyway, iSynCal will scan both locations, giving precedence to the iCal 2 files in case both iCal v1.x and iCal v2.x calendars are found into the user's Home folder. Moreover, in case a folder named "Calendars" is present directly in the user's Home folder or network shared folder it will have precedence over the iCal's folders, as described below; this is useful for certain scenarios were an user account or a network folder are specifically used to share some calendar files located on a server, like in Example 3.
In case you have a Mac running Mac OS X 10.3 "Panther" and you update it to Mac OS X 10.4 "Tiger" doing an "Upgrade Install" to retain your applications, documents and settings (don't worry, that's not Microsoft Windows™) the iCal calendars will be moved to the iCal 2 folder and format only on the first iCal launch under Tiger, therefore I strongly suggest you to launch iCal at least once when you have finished with the Tiger upgrade process.
If List calendars found into ... is set to Network disks iSynCal will scan each mounted network volume to find the calendar files in this order:
./Users/username/Calendars
./Users/username/Library Application Support/iCal/Sources
./Users/username/Library/Calendars
./Calendars
./Library Application Support/iCal/Sources
./Library/Calendars
where the initial dot represents the full path to each of the mounted network disks and username is iterated for each user's folder name found in their Users folder.
You should select this setting when you have to sync your calendars with those located on another computer.
If List calendars found into ... is instead set to This computer iSynCal will scan inside the startup disk's Users folder and any locally attached volume (e.g. a secondary internal or firewire disk either an iPod); it will look for:
./Users/username/Calendars
./Users/username/Library Application Support/iCal/Sources
./Users/username/Library/Calendars
./Calendars
./Library Application Support/iCal/Sources
./Library/Calendars
where the initial dot represents the full path to each of the local disks and username is iterated for each user's folder name found in their Users folder.
You should select this setting when you have to to sync your calendars with other users on the same computer or with an attached iPod or external drive (see also Users or iPod synchronization).
You also have the option to manually select a folder containing the calendars to synchronize by clicking on the small rounded button with the Users folder's icon, located in the Options drawer, and browsing your computer or the network.
When such a folder is selected iSynCal will scan inside it to look for a Calendars folder in the order described above, hence don't select the folder named Calendars: select either its parent or the user's Home folder instead (any Home folder contains a Library folder); when a valid Calendars folder is found it will appear on the right side popup button's list, among the other valid folders found.
To allow advanced users to fully customize the path to the folder containing the .ics calendar files, there is also a specific iSynCal preference to designate an additional custom folder name where iSynCal should look for .ics files, beside the usual Calendars folder.
For example, if you enable the iSynCal preference Also search .ics calendar files into a folder named and then enter MyFolder as the custom folder name then iSynCal will additionally look for such files into the paths
./Users/username/MyFolder
./MyFolder
where the initial dot represents the full path to each of the local or network disks (depending on how is set the option List calendars found into ...) and username is iterated for each user's folder name found in their Users folder.