Screencast-O-Matic stores your recordings by default in the Documents folder on your Mac. Each recording is made up of several different files.
Mac users may find some of their recordings missing due to the use of iCloud's "Optimize Mac Storage" feature. The "Optimize Mac Storage" feature will randomly backup and remove some of the files that make up a recording making it impossible for Screencast-O-Matic to use the recordings.
To access these recordings again, you will need to tell iCloud to return them to your computer.
Open the Mac Finder and click on Documents and look for a Screencast-O-Matic folder. Inside the Screencast-O-Matic folder is a Recordings folder which holds your recordings.
If iCloud has removed files from any recordings then you will see cloud icons next to the recording folder name as shown in the image below.
Click on the icon next to the recording name to tell iCloud that you want that recording back on your computer.
Once you click on the icon a circle will appear showing you the progress while the recording is being recovered from iCloud. When the recording is ready, the icon will disappear.
After the recording is recovered from iCloud you must close and restart the Screencast-O-Matic application to access your recordings again.
If you'd like to stop this from happening in the future then you can: