BusyCal or BusyContacts can be installed on up to 5 computers that you own, using the same registration code.
Depending on where you downloaded the apps from (Mac app store or directly from our website), all you need to do is download the apps again on the new computer and add the accounts you had in your old computer (such as iCloud, Google, Exchange, Fruux, Fastmail and so on).
BusyCal - Manual Migration
BusyContacts syncs with the built-in Contacts app on macOS and iOS and supports all leading cloud services, including iCloud, Google, Exchange and Twitter. BusyCal syncs with the new BusyCal for iOS, which offers the same power, flexibility, and reliability that BusyCal for Mac users have enjoyed for years including customizable Day, Week, Month and List views, integrated To Dos, live weather, tags, and more. It's the ultimate mobile companion to BusyCal.
Re-adding your accounts won't however sync your previously stored preferences though, including any 'On My Mac' calendars. If you care about those, you can perform a manual backup and restore.
BusyCal cares about this folder:
~/Library/Containers/com.busymac.busycal3/Data/Library/Application Support/BusyCal
and this file
~/Library/Containers/com.busymac.busycal3/Data/Library/Preferences/com.busymac.busycal3.plist
You can copy them manually from one computer to another, although you must launch BusyCal once on the new computer to set up the container.
On old computer:
In the Finder, select Go > Go to Folder, and paste the following:
~/Library/Containers/com.busymac.busycal3/Data/Library/Application Support
Grab the BusyCal folder
Busycontacts For Ios
~/Library/Containers/com.busymac.busycal3/Data/Library/Preferences/
Grab the com.busymac.busycal3.plist file
On new computer, launch and set up BusyCal, then quit.
In the Finder, select Go > Go to Folder, and paste the following:
~/Library/Containers/com.busymac.busycal3/Data/Library/Application Support
Copy over the BusyCal folder from your old computer to this location
~/Library/Containers/com.busymac.busycal3/Data/Library/Preferences/
Copy the com.busymac.busycal3.plist file to this location
Busycontacts Serial
Start BusyCal. You will need to re-enter your account passwords, but all other preferences should be copied over.
BusyContacts - Manual Migration
In order to perform a manual restore of BusyContacts from an old computer to a new one, follow these instructions.
BusyContacts cares about this folder:

Busycontacts Ios
~/Library/Containers/com.busymac.busycontacts/Data/Library/Application Support/BusyContacts
and this file ~/Library/Containers/com.busymac.busycontacts/Data/Library/Preferences/com.busymac.busycontacts.plist
You can copy them manually from one computer to another, although you must launch BusyContacts once on the new computer to set up the container.
On old computer:
In the Finder, select Go > Go to Folder, and paste the following:
~/Library/Containers/com.busymac.busycontacts/Data/Library/Application Support

Grab the BusyContacts folder
~/Library/Containers/com.busymac.busycontacts/Data/Library/Preferences/
Grab the com.busymac.busycontacts.plist file
On new computer, launch and set up BusyContacts, then quit.
In the Finder, select Go > Go to Folder, and paste the following:
~/Library/Containers/com.busymac.busycontacts/Data/Library/Application Support
Copy over the BusyContacts folder from your old computer to this location
~/Library/Containers/com.busymac.busycontacts/Data/Library/Preferences/
Copy the com.busymac.busycontacts.plist file to this location
Start BusyContacts. You will need to re-enter your account passwords, but all other preferences should be copied over.
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