LaserJet pro 400 m401n not printing 2 sided

[crslb]

My LaserJet Pro 400 M401n quit printing 2 sided.  It was working but now prints 2 pages when I select print on both sides.  I have uninstalled and reinstalled but that did not help.  What do I do now?

[SHThompson]

Is this possibly in m401dn? If it's really an M401n it does not print 2-sided.

[crslb]

No, it is not a M401dn.  It is a M401n.  I found in can select manually print on both sides but then I have to reverse the order of the pages in order to get page 2 on the same sheet as page 1.  That's a problem when I print 40 pages. 

I use to be able to select Print on both sides and after printing one side, I'd be prompted to reload the paper without changing the order.  It worked really slick

[crslb]

I just found the instruction manual for the M401Series  .  It is located here

Look at Pages 32-34.  The manual specifically says on page 32 that this section primarily applies to M401a and M401n models. 

I can follow the instructions to the letter except for step 4.   Step 4 indicates to select the Print on both sides (Manually) check box.  Both Word and PDF only have Print on Both sides.  

This feature use to work for me.  What changed? 

[crslb]

I found my own answer and am posting in case someone else has the same problem.
First off - the manual link doesn't work.  I google searched for HP m401n manual and found it.

The solution is in the Printer Properties. 

1. Control Panel> Devices and Printers> Right Click printer>Printer Properties
2. Device Settings Tab
3. Under Installable Options, Duplex Unit (for 2 sided Printing) needs to be NOT INSTALLED
   
   When Printing

1. Go to Printer Properties (in Word, Excel, etc), Finishing Tab. Select the Print on both sides (manually) check box. Click ok to print the first side of the job.
2. Retrieve the printed stack from the output bin of printer, maintain the same orientation, place it in Tray 1 with the printed side down and the top of the pages toward the product.

On the control panel, press the OK button to print the secode side of the job. 

Hope this solution helps someone else.  The HP m401n will manually print 2 sided.

[khfbsk]

Thank you for posting this.  It is exactly what I needed!

[khfbsk]

Thank you so much for figuring this out!  I have spent hours today trying to fix this!