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Error 401 and possibly upgrading issues?


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Hello all. Been a long time Nitro 12 user for many years. Over the last number of months I keep getting error 401 every time I started it up. I went online to the FAQ part of the help line and saw that someone suggested that it would all be fixed if only I upgraded to Nitro 13. So I downloaded that file and now am faced with paying for the newer version which supposedly will fix that issue - whatever it was? Furthermore It appears that i cannot access my earlier versions of Nitro now although I have not deleted the 13 files yet. Has anyone else had this issue with the 401 error? If so, how did you fix it so that 12 kept running without any more errors? Thanks, Donald

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Allain Umailin

Hello @dstaples@grandviewenergy.c,

Thank you for reaching out to us through our Community Forums!

The error is related to Nitro attempting to gain access to Cloud services and tends to occur when users leave Nitro Pro 13 idle for a while.

But for Nitro Pro 12, we normally recommend confirming the error message, logging out from Nitro Sign at the upper-right corner of the program, closing then relaunching Nitro Pro, resetting your Nitro Sign password and re-logging into Nitro Sign.

Since you have installed a newer version, please refer to these steps in order to reinstall Nitro Pro 12:

1. Clear the content of the directory under C:\users\your_username\Appdata\local\temp. For whatever reason, not all temp files automatically remove themselves and is NOT usually caused by Nitro Pro files. Kindly note Appdata folder is hidden and to unhide it, please refer to this article https://cybertext.wordpress.com/2012/05/29/cant-see-the-appdata-folder/ 

3. Download and run our Clean Up utility to uninstall your Nitro Pro:  http://install.nitropdf.com/professional_13332645/install-cleanup/install-cleanup.zip

NOTE: This clean-up tool will erase any existing signature files within Nitro so please save them to another location before using the clean-up tool in order to keep them. Please see this link for backing up custom stamps/signatures: https://kb.gonitro.com/knowledgebase#/search/stamps/000004307 

4. Clear all your downloads folder or delete all downloaded Nitro installers. This step is important because we noticed that if you are saving all the installers and you download them in the same folder (like the downloads folder), the EXE can pick up any MSI installer in that folder and you may pick-up one of the older builds instead of the newly downloaded package.

5. Download and install Nitro Pro 12.16 using below offline installers:

x32 http://install.nitropdf.com/professional_12163574/en/retail/nitro_pro12_ba_x86.msi
x64 http://install.nitropdf.com/professional_12163574/en/retail/nitro_pro12_ba_x64.msi 

To know if you have 32-bit or 64-bit, please refer to this article:  https://support.microsoft.com/en-ph/help/15056/windows-32-64-bit-faq 

6. After installation, you can activate by opening Nitro Pro, clicking on the Help tab > About Nitro Pro > Activate by entering your serial number

7. Reset your Nitro Sign password, login back to Nitro Sign by clicking 'Log In' button.

Thank you for choosing Nitro and I hope this helps.

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Thanks Allain! Very helpful and i have just followed the recommended steps and am back using my Nitro 12 Pro steadily. Very much appreciate the help.

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