Why do random lines appear while writing with Apple Pencil?

Random horizontal or vertical lines while you write in Goodnotes can interrupt your notes and feel frustrating, especially when writing is a core part of how you use the app.

Please note: This issue usually affects Apple Pencil on iPad and iPadOS. It is widely reported across writing apps and is most often caused by Apple Pencil or iPad hardware—not a Goodnotes-specific bug.

Example of random lines appearing while writing with Apple Pencil in Goodnotes

Why random lines appear

These stray strokes are typically a touch-input problem between your Apple Pencil and iPad. Users who replace their Apple Pencil or iPad often report that the random lines stop. If basic troubleshooting does not help, report the issue to Apple or ask Apple Support about a hardware replacement.

What to try

If you have already tried a few fixes, jump to the section that matches what you have not tested yet.

Quick checks first

Start here if you have not tried the basics yet.

Run our Apple Pencil troubleshooting basics to check for common setup issues.
Try a different pen style. Some users see the issue only with pressure-sensitive tools (Brush, Fountain pen), while others see it with Ball Pen or highlighter.
Clean or replace the Apple Pencil tip. Unscrew the tip, wipe the tip and sensor area, then reattach firmly.
Reconnect Bluetooth. Turn Bluetooth off and on in iPad settings, then reconnect your Apple Pencil.
Keep the screen dry. Sweat, moisture, or water on the screen can affect how the Pencil registers input.

Check your writing setup

Try these if quick checks did not help.

Adjust palm rejection in Goodnotes. Higher palm rejection can reduce strokes from your palm being mistaken for the Pencil. See Configure palm rejection for comfortable writing.
Change or remove your screen protector. Tempered glass protectors can interfere with Apple Pencil input.
On Apple Pencil (2nd generation), change or disable double-tap sensitivity in iPad settings. See Apple's guide to Apple Pencil settings.
Turn off Zoom in iPad settings under Accessibility. Some users reported that Zoom caused stray lines while writing.

Reduce interference

Try these if the issue happens in specific situations, such as while charging or using a case.

Avoid using your iPad while it is charging.
Remove thick cases.
Keep the iPad away from other electronics.
Use a non-metallic surface.
Touch a metal edge of the iPad to discharge static.

If it still happens

Try these only after the steps above.

Reinstall Goodnotes. Back up your library first with Auto Backup or manual backup, then delete and reinstall the app.
As a last resort, back up your iPad and reset your iPad. If you are unsure, visit an Apple Store for help.

If the issue continues

If none of these steps help, contact Apple Support. Because this behavior is usually hardware-related, a replacement Apple Pencil or iPad is often the most reliable fix.

References

Community discussions and videos about this issue: