@S2794, Welcome to the HP Support Community!
Thanks for reaching out about your query regarding your HP Envy 6400e!
We're thrilled to have the opportunity to assist you and provide a solution.
I understand that your HP Envy 6400e printer is not waking up from sleep mode unless you unplug and reconnect the power. I’ll be happy to help you with this issue.
Here are some steps you can try to resolve the problem:
Update Printer Firmware:
- Make sure your printer firmware is up to date:
- Open the HP Smart app (or go to 123.hp.com to install it).
- Select your printer and check for any available firmware updates.
Disable Sleep Mode:
- On the printer control panel, go to Settings→ Power Management.
- Adjust or disable the sleep mode settings.
Reset the Printer:
- Turn off the printer.
- Unplug the power cable from the printer and the wall outlet.
- Wait for about 60 seconds.
- Reconnect the power cable and turn on the printer.
Reinstall the Printer Drivers:
- On your computer, go to Control Panel→ Devices and Printers.
- Remove the printer.
- Download and install the latest drivers from the HP Support website.
Set Printer as Default:
- On your computer, go to Settings→ Devices→ Printers & Scanners.
- Select your printer and set it as the default printer.
Test Printing:
- Try printing a test page to check if the issue is resolved.
If the problem persists, please let me know. We’ll be happy to look into it further for you.
Take care, and have an amazing day!
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Regards,