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My Printer Is Only Printing Half My Print

3rd June 2020 Printing

This is a common problem with USB printers and there are several main reasons it can occur:

  • Problem with the print spooler (on Windows PCs)
  • Overload of the GPU on later model Macs
  • Dodgy USB cord
  • Dodgy USB port
  • Skew detection or some other sort of automatic checking kicking in

We discuss each one below.

Problem with the print spooler on Windows PCs

Sometimes there can be some left over data in your 'print spooler' - the temporary area data is stored in as it is handed off to the printer.  This can cause all sorts of issues with prints, including prints that only partially complete.

To fix a print spooler issue is relatively easy and this usually solves the problem.

  1. Click "start" and go to "Run"
  2. Type "services.msc" at the prompt which will open the Services window
  3. Scroll down the alphabetical list in the right window pane until you come to the entry with the name "Print Spooler
  4. Right-click this entry, then select "stop". This will stop the computer running the process that holds your print queues
  5. Leaving that window open for now, click again on "Start", and then click "My Computer" to open a Windows Explorer window
  6. We've stopped the queue service, now we just have to clear the jam that is already there. To do this we navigate to the print spool folder which is hiding within the Windows folders. Usually Windows is installed on C: drive, but you should be easily able to tell when the Explorer window opens which drive it is on.
    The usual path to the spool folder is C:\WINDOWS\system32\spool\PRINTERS, but yours may be slightly different. Your windows drive may have another name for instance, but this would be uncommon. So click on your Windows drive (usually C), then double-click on the Windows folder, and then find the System32 folder and double-click on that. Windows may warn you that you are about to view system files, but click "View files anyway" message and search out the "spool folder". Within the Spool folder is your Printers folder, and you should open that
  7. Delete every file within this folder to empty the jammed print queue (pressing the "ctrl" and "a" keys will select all files and then you can just hit "delete").
  8. Close the explorer window now that we have emptied the cleared spool files, and return to your Services window. we must re-start the Print spool service, and do so by right-clicking the Print Spool entry and selecting "Start" from the list. Close the services window and try printing again.

Overload of GPU on Macs

Recent MacOS versions (certainly from 10.15 on, but it might be the same for earlier versions too) - use the GPU (Graphics Processing Unit - i.e. video card) - for a lot more general processing, including spooling files to printers.  If the GPU is overloaded, it can cause image processing during spooling to fail.  Unfortunately you don't get any particular warning or message about this....just another sheet of wasted paper!

In particular this often seems to occur in multi-monitor set ups.  So try detaching any extra monitors as a first step.  And/or try closing any GPU intensive applications during printing (includes things like graphics / raw processing applications, but also modern browsers are GPU intensive, and so on).  

Dodgy USB Cord or Port

If you have tried to fix the GPU and/or print spooler issues as detailed above, and you are still having issues, it may be the case that your USB cord or port is not working correctly. Try a different USB cord or port and this will often solve the problem.

For Macs

If you've checked your USB connections, then you can sometimes solve persistent issues like this by resetting the entire print system, but please note: this loses all your printers & print settings, so it's quite drastic. Apple have a support note with the process here.

Skew Detection & Other Automatic Checks

Modern printers have various fancy features designed to 'help' you wit your printing.

One of the most frequently frustrating is 'skew detection'.  Basically, the printer tries to detect if the page is not feeding perfectly squarely through the printer.  If it detects (often, it seems, incorrectly) - that the page is ever so slightly skew-iff, some printers will simply spit out the half done image at that point - and of course without even providing any sort of informative message.

Great design, huh?

Our advice is to turn off all of those sort of automatic checks - they usually do more harm than good.  We habitually turn off skew detection, automatic nozzle checking, and anything else it claims to automatically check.  Of course we do then run regular manual checks.  But in the case of, e.g. skew detection - I'd rather my print come out in full and be a mm or two not square on the page than waste a whole sheet of paper and ink when the printer decides three quarters of the way through that thing are screwy!