You are not alone. Our Canon MG4250 WIFI printer had been hitting us with the "Another computer is using the printer" error message on a daily basis until we finally cracked and looked into this infuriating printing problem. We found a solution so we'd like to share it just in case it helps you with your own printing problems. (It may not just be Canon printers ... Epsons appear to be affected too).
DISCLAIMER: this advice is given in good faith. You use it entirely at
your own risk. We are not technical people or IT people so if you crash, corrupt, upset or mess up your
PC or laptop in the process our obligations are limited to providing words of comfort only
(limited to 75 words for each event). We are running Windows 10 so we're not sure if
this works with other versions of Windows (?)
OK. Here we go then. All you need to do is follow the instructions below:
So that solves the problem with our Canon Pixma MG4250 printer displaying the warning message "Another computer is using the printer". We've noticed on other websites that this printing problem occurs with other models including the Canon MG5420, MG6450, MX 470 and MX512 which also display this error on occasion. It also seems to curse some Epson printers.
Thanks for the thanks ... you're all very very welcome ....
3rd May 2018: VH contacted us to express their gratitude for this information which helped to fix this problem with an MB2040.
10th May 2018: DB emailed to say thanks and that these instructions were very easy to follow even for the computer illiterate. They were running Windows 10.
7th June 2018: PR said "This fix worked perfectly and I was really struggling to find a solution"
22nd July 2018: NN got their Canon MX920 working (Windows 10)
26th July 2018: PM thanked us for helping with his Canon IP7250 and questioned the fidelity of his printer because it spends so much time occupied with a stranger.
26th July 2018: MM had success with Windows 10 and a Canon 922.
August 2018: J finally made peace with her MG6851. She says the problem often occurs if she hasn't switched the printer on before sending a print. We've experienced that too.
October 2018: JT fixed her MG5400 (and promised us a share of her next lottery win!), JC now has a functioning MG5550 and M said our solution was "much easier, faster and more straightforward than Canon's tech advice". We'll take that!
February 2019: RC wrote "Our Canon MX490 would like to thank you for saving it from being thrown against a wall, stomped on, whipped around by its cord and finally unceremoniously deposited in the garbage for shredding. Our printer is once again a functioning member of our family."