Hi! I see that PDF documents are opening very slowly for you in PDF Gear on your Windows 10 device. Let me help you with that. To get started, could you let me know if this happens with all PDFs or just specific ones? Also, how long does it typically take for a PDF to open? This info will help me tailor the troubleshooting.

Meanwhile, here are some initial steps you can try to improve PDF opening times in PDF Gear:

1. Close Unnecessary Programs or Browser Tabs: Having many programs or tabs open can use up system resources and slow down app performance. Try closing those you don't need and then open your PDF again.

2. Check for Large or Complex PDFs: Sometimes very large files or those with many images or detailed elements can load slower, especially on lower-spec machines.

3. Clear PDF Gear Cache:
- Although mostly for mobile, clearing cache can help on desktops too by resetting temporary data.
- Try closing PDF Gear completely, then reopen it. If there's an option in settings to clear cache or temporary files, do so.

4. Set PDF Gear as Default PDF Viewer: If you’re opening PDFs from Explorer, setting PDF Gear as the default app can sometimes speed up opening.

5. Update PDF Gear: Make sure you have the latest version installed; newer versions often have performance improvements.

6. Restart Your Computer: A fresh reboot can clear any stuck processes slowing down your apps.

If after these steps your PDFs still open slowly, I can guide you through checking system performance issues like RAM usage or advanced app settings.

Could you try these and let me know what changes you observe? Also, please share any details about the files or how slow “slow” is in your case. That way, I can assist further!