On the desktop app, Heptabase stores your full data on your computer so you can work offline, which uses local disk space. If that drive's free space drops below 10% of total capacity, the offline storage can't keep working reliably, which is what triggers this notification.
Check what's using the space
Open the Heptabase data folder and look at the size of the hepta-files subfolder, which holds your imported PDFs, images, and other attachments:
Windows: paste
%USERPROFILE%\AppData\Roaming\project-metainto File Explorer's address bar.macOS: in Finder, press Cmd+Shift+G and paste
~/Library/Application Support/project-meta.
If hepta-files is 1 GB or larger, your imported files are the main culprit. If it's smaller, the disk is full from other apps or files outside Heptabase.
Free up space
If
hepta-filesis large, contact support. We can help move it to another drive.Otherwise, delete unused files on the affected drive directly.
As a workaround, use the web app instead. The web app runs in your browser and doesn't require local storage.