Software

that adobe error is the install cannot write a registry key.

https://www.google.com/search?client=firefox-b-1-d&sxsrf=ACYBGNTYRnhX7_JrOBIZAl562kbxmBa9mQ%3A1569010195723&ei=EzKFXfnNK86V0PEPwbSNiAU&q=adobe+pro+error+1406&oq=adobe+pro+error+1406&gs_l=psy-ab.3..0i8i30l2.224983.225575..226300...0.2..0.89.341.4......0....1..gws-wiz.......0i71j35i39j0i7i30j0i8i7i30.vj8hS1RF54o&ved=0ahUKEwi5o_W6muDkAhXOCjQIHUFaA1EQ4dUDCAo&uact=5

This article from Abode may be of use:

https://helpx.adobe.com/acrobat/kb/error-1402-error-1406-acrobat.html

It mentions trying to remove old versions (may not be want you want) and also setting permissions for this registry key.

The OS is a little dated on this but it should still follow the same basic methods.

So most update issues for pre-subscription  Adobe applications can be traced to either Adobe Application Manager (AAM) or tp having Adobe Flash installed. If AAM is later than AAM 6.2 then you will need to uninstall remove left over folders and reinstall.

Application manager is Adobes background update tool. During the transition to the Subscription model AAM went from 6.2 the last update version to support the perpetual licensing model to AAM 8.0 which is the subscription version.

So if you install any perpetual Adobe software for example CS6 or earlier, when online the very first update is AAM to 8.0 which is the subscription licensing model and you wont be able to update. It will only do an AAM update and ask you to reboot. If you are online after the reboot it will claim you need a subscription to update.

If you try to manually update offline you still wont be able to update CS6 until you update AAM to version 6.2.

For Acrobat 9 Std, Pro, and Pro Ext you need to install offline so it doesn't automatically do a background update to version above AAM6.2. Also to update to version 9.5.5 you will need all the updates available offline to install them.

I put together a batch file to do an all at once update to install all the Acrobat 9 updates and placed all the updates on line at the Internet Archive so they'd be easily accessible in one location without a lot of clicking on to the old Adobe updates page. That was really messed up how they had their update download section. The old Adobe update webpages are still accessible on Archive.org if you have the original link.

Here's the Internet Archive page I put together that contains all the updates - Acrobat updates to version 9.5.5

You can choose to download the individual acrobat updates or an ISO file that contains them all. There is a batch file, as a single download, to do an "All At Once" update and one inside the ISO that with install all the updates at one time.

The same batch file can be modified to install Acrobat X and XI updates by substituting the version 10 or 11 updates in place of the version 9 ones.

Also included at the link above is the version 9 3D update and the Indexer update.

You will need to uninstall, then delete any left over Adobe folders, then reboot

1. To install disconnect from the internet so it can't do a background update while installing.

2. Install the version of Acrobat 9 pro you have. When finished don't reboot

3. Install all the updates.

This is for the Pro versions only. The Acrobat 9 standard version has a different 9.1.0 update then the pro version although all the other updates will work to update it.

If you have a Pro key then you could use the Acrobat 9 Pro ISO I put together that has all the updates integrated into the setup routine. This ISO is also on the Archive.org here Acrobat 955 Pro Ext