Nitro Pro 10 - Stamp Tool Freezes

(Windows 10)

Internal troubleshooting guide for Lan IT technicians

Issue overview

Troubleshooting flow

Stop after the first step that resolves the issue.

Before you begin

• Save any open PDFs in Nitro and close Nitro Pro completely (end the task in Task Manager if needed).
• If the user has custom stamps they care about, back up the stamp files before doing any uninstall steps.
• Confirm the issue is reproducible by opening a local PDF and attempting Review > Stamp.

Background (why this happens)

Nitro stores custom stamps in the user profile (under %AppData% ...\Nitro\Pro\Stamps). Image-based stamps are stored in user_stamps.pdf, while text-only stamps are stored in user_stamps.cnf. If these files become corrupted, opening the Stamp menu or Manage Stamps may hang.

Step 1 - Reset the Stamp cache (user stamp files)

This step rebuilds the two files Nitro uses for custom stamps. It is non-destructive if you back up the files first.

Procedure

1) Close Nitro Pro completely.

2) Open the Stamps folder:

• Run dialog: %appdata%\Nitro\Pro\10.0\Stamps
• Alternate folder: %appdata%\Nitro\Pro\10\Stamps
• Search: Search within %appdata%\Nitro for user_stamps.pdf

3) Back up:

• user_stamps.pdf
• user_stamps.cnf

4) Rename (do not delete):

• user_stamps.pdf -> user_stamps.pdf.old
• user_stamps.cnf -> user_stamps.cnf.old

5) Re-open Nitro and test Review > Stamp.

Verification

• Stamp menu opens immediately and does not freeze.
• A standard stamp (for example, Paid/Reviewed) can be placed on a PDF.

Rollback / recovery

If custom stamps are missing after the reset, close Nitro and restore the backed up files by removing the .old extension.

Step 2 - Repair / reinstall Nitro Pro 10 (standard)

Use this step if Step 1 did not resolve the freeze.

Procedure

• Open Control Panel > Programs and Features (or Settings > Apps).
• Select Nitro Pro 10 > Change (if available) and run Repair.
• Reboot Windows and re-test Review > Stamp.

If Repair is not available

• Uninstall Nitro Pro 10, reboot, then install again (use your internal software repository or the installer you have on hand).
• Activate: Help > About Nitro Pro > Activation and enter the serial number.

Step 3 - Clean uninstall + reinstall (Nitro Clean Up utility)

This step removes Nitro more thoroughly than a standard uninstall and clears old installer artifacts.

Procedure

• Clear C:\Users\<username>\AppData\Local\Temp (delete contents Windows allows).
• Download cleanup.zip, extract to Desktop, run it, then reboot.
• Delete old Nitro installers from the Downloads folder (prevents older MSI/EXE packages from being reused).
• Install Nitro Pro 10 (10.x.x.x) using an offline installer from your internal software repository, then activate using Help > About Nitro Pro > Activation.

Download links

Nitro Clean Up utility (community link): http://install.nitropdf.com/support/downloads/cleanup.zip

Offline installer: Use the Lan IT software repository or Nitro-provided installer media for Nitro Pro 10 (10.x.x.x).

Additional checks (if needed)

Use these checks to rule out file-specific or environment-specific causes.

• Test Stamp on a different PDF saved locally (for example, Desktop) to rule out a file or network location issue.
• Run Nitro once as Administrator (right-click Nitro Pro > Run as administrator).
• Temporarily disable third-party PDF add-ons or security software that hooks into PDF processes, then re-test.
• Check Windows Event Viewer for application errors related to Nitro at the time of the freeze.

Escalation package (what to capture)

• Nitro Pro version (10.x): Help > About Nitro Pro (screenshot).
• Windows version/build: winver screenshot or text.
• Exact reproduction steps and whether the freeze happens on all PDFs or only specific files.
• Whether Step 1 recreated new user_stamps files after relaunch.

References

• Nitro user guide (Windows) - Add a Stamp: https://www.gonitro.com/user-guide/pro/article/add-a-stamp
• Nitro quicklinks - Creating & Using Stamps (screenshots): https://cs.gonitro.com/quicklinks/stamps/
• Nitro Community - Stamp storage and user_stamps files: https://community.gonitro.com/topic/3269-dynamic-custom-stamp-options-firm-name-and-date-only/
• Nitro Community - Pro 10 clean uninstall + activation guidance: https://community.gonitro.com/topic/4627-reinstall-of-nitro-10-isnt-working/