Start with this diagnostic checklist
Before changing files, note:
- Which Canon printer model is installed, if known
- Whether the error appears during Windows startup, printing, or Canon software installation
- The exact wording: missing, not found, could not be loaded, entry point not found, or specified module not found
- The executable named in the error dialog
- Whether Windows is 32-bit or 64-bit
- Whether the printer still appears under Settings > Bluetooth & devices > Printers & scanners
- The file path shown by the error or security software
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cnbp_303.dll is a Canon printer-driver component, not a normal Windows application DLL. When cnbp_303.dll is missing or cannot be loaded, the safest fix is to remove the damaged Canon package and reinstall the complete driver for the exact printer model.
What cnbp_303.dll belongs to
The file is described as Canon Inkjet Printer Driver and is associated with older Canon PIXMA driver packages. Public driver records connect it with packages using prnca00b.inf and models including the PIXMA iP1900, iP2600, MP190, MX850 and MP980 families. That list should not be treated as a complete catalog of every compatible Canon printer.
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This is a hardware-driver file. It is not a Visual C++ runtime, DirectX component, .NET file, or universal Windows DLL. It may appear below:
C:WindowsSystem32DriverStoreFileRepository
The DriverStore is where Windows keeps installed driver packages. Do not manually replace files in that location. Windows manages those files through driver installation and servicing, and copying a DLL there can leave the package inconsistent.
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The exact file version, architecture and supported Windows releases are not reliably documented in the available Canon material. A third-party file index reports metadata for one copy, but that is not a Canon-confirmed version record.
Fix 1: Reinstall the complete Canon driver
This is the most likely solution for a missing or corrupted file.
1. Identify the printer
Open Start > Settings > Bluetooth & devices > Printers & scanners on Windows 11.
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On Windows 10, open Start > Settings > Devices > Printers & scanners.
Select the Canon printer and record its full model name. If it is not listed, check the printer label, its original documentation, or the Canon software name shown in the error.
2. Remove the printer
In the printer’s settings, select Remove or Remove device. Confirm the removal.
Then open Apps > Installed apps in Windows 11, or Apps > Apps & features in Windows 10. Remove Canon printer software associated with that model, including old setup utilities or maintenance programs.
Restart Windows after uninstalling.
3. Download the correct package
Use Canon’s official support site and search for the exact printer model. Select the driver intended for your Windows version and system architecture.
Do not select a package only because its name contains a similar PIXMA model. Older Canon drivers can share files while still having different model coverage.
If Canon provides several downloads, prefer the complete printer driver or installation package rather than a utility alone. Save the installer locally before running it.
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4. Install it normally
Right-click the downloaded installer and select Run as administrator if Windows allows that option.
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Follow the setup wizard:
- Accept the license terms.
- Choose the normal or recommended installation.
- Connect or power on the printer only when the installer requests it.
- Allow the setup to copy and register the complete driver package.
- Restart Windows if prompted.
Print a Windows test page from Printers & scanners > your Canon printer > Printer properties > Print Test Page.
The repair worked if the error no longer appears and the test page prints. If setup stops with the same DLL error, continue with the architecture and cleanup checks below instead of copying cnbp_303.dll manually.
Outbyte Driver Updater can reduce the manual work of hunting through driver versions and checking which installed hardware packages are stale. Its free scan shows what it finds, while driver installation through the full version is optional; for this specific file, the exact Canon model package remains the authoritative source.
Fix 2: Check for an old Canon package and printer queue
A removed printer can leave behind software that still starts with Windows or is called when the Print Spooler processes a job.
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- Open Settings > Bluetooth & devices > Printers & scanners.
- Remove duplicate Canon entries and entries for printers you no longer own.
- Open Control Panel.
- Select View devices and printers.
- Right-click unused Canon entries and select Remove device.
Restart the Print Spooler
- Press Windows key + R.
- Type
services.mscand press Enter. - Find Print Spooler.
- Right-click it and select Restart.
Try printing again.
If the error appears only when printing, removing the old queue and reinstalling the model-specific package is more relevant than repairing Windows system files. If the error appears at every startup, inspect the executable named in the dialog. It may be an obsolete Canon utility still pointing to a removed driver.
Fix 3: Check 32-bit and 64-bit compatibility
A 64-bit Windows installation can still use legacy 32-bit printer components. The folder name alone does not prove that a driver is compatible or incompatible.
To check your Windows architecture:
- Open Start > Settings > System > About.
- Find System type under Device specifications.
- Note whether Windows is 32-bit or 64-bit.
Use a Canon package that explicitly supports that Windows installation. An older package designed for Windows XP, Vista or Windows 7 may install incompletely on a current system, or it may produce an entry-point error when an old component loads.
If Canon no longer provides a compatible package, try Windows’ built-in printer support only if it exposes the features you need. Basic printing may work while scanning, maintenance, borderless printing or ink monitoring does not.
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1Scan for outdated or missing drivers - takes under a minute2Clear out junk files and repair common Windows errors3Fix the driver behind crashes, sound loss and screen glitchesFix 4: Check Microsoft Defender quarantine
A security product may have quarantined the driver file. Do not restore an unknown copy simply because its filename matches.
- Open Start > Settings > Privacy & security > Windows Security.
- Select Virus & threat protection.
- Select Protection history.
- Review detections related to the Canon installer or printer driver.
- Expand a detection to inspect its path and source.
Restore the file only when it came from trusted Canon installation media and the detection has been evaluated as safe. The safer alternative is usually to download the complete driver again from Canon and reinstall it.
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Do not disable antivirus protection to force an unknown DLL into System32. A copy outside the Canon driver package, especially in an unusual temporary or user folder, should not automatically be trusted.
Fix 5: Repair Windows components with DISM and SFC
Windows repair commands are useful when the error appears alongside failures involving several unrelated system files, Windows installation components, or the DriverStore. They do not replace a missing Canon package.
First install pending Windows updates.
On Windows 11:
- Open Start > Settings > Windows Update.
- Select Check for updates.
- Install available updates and restart.
On Windows 10:
- Open Start > Settings > Update & Security > Windows Update.
- Select Check for updates.
- Install available updates and restart.
Then repair the component store:
- Open Start.
- Type Command Prompt.
- Right-click Command Prompt and select Run as administrator.
- Run:
DISM.exe /Online /Cleanup-image /Restorehealth
Wait for it to finish. Next run:
sfc /scannow
Restart Windows when SFC completes, then test the Canon printer again.
DISM repairs the Windows component store, while SFC checks protected Windows files. If both commands complete without resolving the Canon error, return to the Canon driver package rather than repeating them indefinitely.
Outbyte PC Repair can make component troubleshooting less repetitive by showing what its scan finds before repair. Its free scan identifies reported issues, while repair through the full version is optional; DISM and SFC remain the built-in Microsoft repair path.
Fix 6: Use System Restore after a recent change
If the error began immediately after a driver update, Windows reinstall, cleanup utility, or software removal, System Restore may reverse the change.
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- Press Windows key + R.
- Type
rstrui.exe. - Press Enter.
- Select Next.
- Choose a restore point from before the error began.
- Select Scan for affected programs if available.
- Confirm the restore point and select Finish.
You can also open Control Panel > Recovery > Open System Restore.
After Windows restarts, check the printer. If the error returns, reinstall the correct Canon package rather than restoring an isolated DLL.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Do not run regsvr32 on this file by default
regsvr32 is intended for DLLs that expose a registration entry point such as DllRegisterServer. A printer-driver component is normally installed through its INF file and complete driver package.
Running:
regsvr32 cnbp_303.dll
will not repair a missing dependency, wrong architecture, incomplete Canon installation, or corrupted DriverStore package. It can also produce a misleading “entry point” or “module” error.
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Use the Canon installer instead. Only run a vendor-provided registration command when the official installation instructions specifically require it.
What each error message usually means
- “The program can’t start because cnbp_303.dll is missing”: the Canon component or its package is incomplete, removed or quarantined.
- “cnbp_303.dll was not found”: the calling program cannot locate the file in the expected driver installation.
- “The specified module could not be found”: the named DLL may exist, but a dependency required by it may be missing.
- “The procedure entry point could not be located”: the installed components may be from mismatched driver versions or architectures.
- “Cannot register cnbp_303.dll”: registration may be inappropriate for this driver component, or the file may not expose the required registration function.
- “Not designed to run on Windows”: the file may be corrupted or incompatible with the current Windows environment.
Record the executable and full path shown in the dialog. A Canon installer, printer utility, spooler-related process and stale startup program require different cleanup decisions.
Why you should not download cnbp_303.dll separately
Random DLL download sites can provide malware, the wrong architecture, the wrong language, or a version that does not match the rest of the Canon driver. Replacing only the named file also leaves missing dependencies, INF entries, services and printer configuration untouched.
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One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchUse the exact Canon driver package, Windows Update, or a compatible built-in Windows printer driver instead. Never place an unverified copy in System32 or overwrite files in DriverStoreFileRepository.
FAQ
Is cnbp_303.dll a Windows DLL?
No. It is associated with Canon’s inkjet printer-driver package. It is not a standard Windows, Visual C++, DirectX or .NET component.
Which printers use it?
Public driver records associate it with older Canon PIXMA families including iP1900, iP2600, MP190, MX850 and MP980 models. The available records are not an exhaustive Canon compatibility list.
Should I install Visual C++ Redistributable?
There is no evidence that Visual C++ Redistributable is the primary fix for this file. Repair the Canon printer driver first.
Does SFC fix cnbp_303.dll?
SFC can repair protected Windows files. It does not normally recreate a missing Canon driver package. Use DISM followed by SFC when Windows component corruption is also suspected.
What if Canon no longer offers my driver?
Try Windows’ built-in printer support if it provides the features you require. If it does not, a compatible replacement printer may be the practical solution. Compatibility depends on the exact printer model and Windows version.
What information should I provide for further diagnosis?
Record the printer model, Windows version and architecture, exact error text, executable named in the dialog, file path, and whether the printer appears in Printers & scanners. Also note whether reinstalling the complete Canon package changed the error.
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