After launching Adobe Photoshop, extensions didn't load properly, including Ceacle Mockup, it may be due to a setting in Adobe Photoshop Preferences. Windows: Go to Edit > Preferences > Plug-Ins. MacOs: Go to Photoshop > Preferences > Plug-Ins. If unchecked, check the ‘Load Extension Panels’ in the Filter and Extension Panels group. When this preference is checked, the Ceacle Mockup panel will load on start-up. Restart Photoshop for the changes to take effect.