Most of the time Capture One will not open due to the following:
- You are running an incompatible operating system, i.e. macOS 10.14.6 (Mojave) with Capture One 11
The only options here are to upgrade to the latest version of Capture One or to downgrade your operating system.
See which OS versions are compatible with your version of Capture One here: Which version of Capture One will work on my Apple operating system? / Which version of Capture One will work with my Windows operating system?
You can view your upgrade options by entering your license key here: https://www.captureone.com/en/store/upgrade
- The database you are trying to open is damaged or corrupt
Open Capture One by holding down the Option (Mac) or Alt (Win) key, after initialising the application. This will prompt a window to appear on the screen, whereby you can choose to create a new database (catalog or session) or open a previously used, healthy database.
- The application is still running in the background (Windows)
Use Ctrl + Alt + Delete to access the Task Manager and end any Capture One processes running in the background.
- OpenCL is failing to initialise and causing a crash
See our help center articles on this issue here: What does OpenCL do and how do I use it in Capture One? / Troubleshooting OpenCL
To disable OpenCL in Capture One in case of a crash on startup, follow the steps below:
Windows: Run the script DONOT_useopencl.reg and restart Capture One (the download also contains a restore script to re-enable OpenCL useopencl.reg) Download here.
MacOS: Download AdjustOpenCL_External.zip and run this application AdjustOpenCL_External.app, disable OpenCL, and restart Capture One.