Patch and be happy! (A solution)

Any issues, problems or troubleshooting topics related to installing the Prepar3D client application or it's installer.
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Postby Cruachan » Wed Oct 08, 2014 1:11 pm


Quote from Pidder on October 8, 2014, 10:03

Jacques, sometimes it is better to write nothing than to write nonsense in this thread!

We all know how to do a new full install but that is exactly what we want to avoid.

Mike, as you've seen at my registry string I'm using the Professional Edition of P3D.

All the installation/update process worked as you described it.

Bye from Berlin, GER


Hi Markus,

Ah, I must have missed that, thanks. The reason I asked was to clarify why I'm not seeing the 'License ID' entry under 'SimConnect Version' in your screen capture. I hold an Academic Licence.



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Postby Cruachan » Wed Oct 08, 2014 1:42 pm


Quote from jacquesvde1 on October 8, 2014, 09:36


Simply uninstall your current version and download and install the full 2.4.

That's what I always do and I have no problem with P3DV2. (new release).

I never use the patch.

Jacques ;)

Hi Jacques,

When you have spent a huge amount of time carefully setting up a stable well-performing installation with several weighty Addon enhancements, why on earth would you rush to destroy it every time an incremental patch update is released? Just doesn't make sense. You are, of course, perfectly at liberty to follow the reinstall path, but that is your choice. We choose to patch wherever possible. Hitherto, some, like me, have found that to be a significant obstacle and, it has to be said, received very little in the way of positive support or encouragement. Posts like yours were common and, to be frank, really quite unhelpful. Also, we were starting to see posts from several members who were discouraged enough to state they were remaining on v2.3 rather than spend more time battling with this issue.

Those who have, for whatever reason, been thwarted from following the Patch Updating route now have a relatively painless way of achieving that objective. Please allow us to take pleasure from that fact just as you, Jacques, are now enjoying having accomplished a fresh full reinstall.

Now, at last, there is an opportunity for everyone to be on the same page with the latest version of Prepar3D v2.

IMHO full reinstalls should be reserved for irretrievably broken installations and major version number releases.

Kind regards,


Edit: Wow!! I love your home cockpit. Very impressive!!

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Postby jacquesvde1 » Wed Oct 08, 2014 2:30 pm

Hello Mike :D

OK, I understand, thank you for the tutorial.

Sorry it had confusing. :?


Jacques ;)

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Postby Cruachan » Mon Oct 13, 2014 11:05 am


This is just a heads up to say that a more streamlined version of this guide will appear shortly on this forum. Essentially the 12 Steps remain unchanged, so no need for any panic attacks! Nothing has really changed, just revised to provide further clarification. Also it has been rewritten to be less version specific assuming, of course, that the method continues to work with future Patch Updaters.

You may wish to bookmark the link to the guide unless, of course, it is elevated to 'sticky' status. For future reference, there will be an embedded link in the new version of the guide to this original thread.


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Postby Cruachan » Tue Nov 04, 2014 8:09 am

Seems the new forum software has destroyed any cross-linking to other threads. If any of you are reading this thread and are wondering what has happened to the original post implied by the subject title then join the club! Here is the updated link to the 'more streamlined version':

.....AND here is a copy of the missing original post in this thread:


I am a Prepar3D Academic Licence holder. The assumption is that what follows will also apply to the Professional version of the Patch Updater.

[b]Those of you experiencing problems with the Patch Upater[/b] doubtless will be all too aware of the frustrations it has caused. Well, that now infamous "Could not write value Complete to key...." error can, in my humble opinion, be safely consigned to archival oblivion as a coding folly. Same, I believe, can be said for the Permissions issue which has occupied so much of my time recently as I have tried to troubleshoot the problem. Indeed, I am becoming convinced that there may never be an answer, but time will tell. That said, [b]it remains important for you to be logged onto your computer with Administrator Privileges[/b] and it would be sensible to run, when available, every executable as Administrator. This option is not available to .msp patching files nor, for the purposes of this exercise, does it seem to be necessary.

In fact, the solution, or probably more aptly 'the workaround', has previously been mentioned in one or two posts since the most recent Patch release but, for whatever reason, has never been highlighted nor shouted about from the rooftops! Why? I suspect the main reason is that those of us who read it could not believe that it would work and so dismissed it out of hand without at least attempting the process ourselves.

What has been puzzling me is the difference in behaviour between the Full Installer and the Equivalent Patch Updater. The former achieves a good install, albeit, as with the Patch Updater, the appearance of the "Could not write value Complete to key...." error. Whereas the latter executes what is, in effect, a rollback and installs nothing. This puzzled me until I read a recent post by 'Irontower' in this thread:

I suddenly realised what may be at the root of this difference in behaviour: in the case of the Full Installer it is expecting a clean start with nothing previously in place. So, I asked myself, if we could ensure the same exists for the Patch Updater would this change it's behaviour? The answer appears to be a resounding YES!

However, before embarking on this test I needed a full listing of all the files updated by the Patch Updater. That would allow me to validate the update before copying and pasting files and running the patched Prepar3D for the first time. Again my grateful thanks go to 'Irontower' for the provision of said list.

Now, I'm assuming you are still running a stable working [b]Prepar3D v.2.3.11345.0[/b] with or without various Addons.

[b][i]Here are the steps required to update to Prepar3D v.2.4.11570.0[/i][/b]

[b]1..[/b] Rename the existing 'Prepar3D v2' folder to '[b]xxxxxx[/b]'. Name is not important, but the string of x's will help avoid any accidental copying and pasting from the wrong folders as you will see later.

[b]2..[/b] Create a new folder at the same location and rename it '[b]Prepar3D v2[/b]'. This serves as a temporary location for all the Patch files. Meantime it remains empty.


[b]3..[/b] Backup the following 4 folders to a safe location:

[b]%PROGRAMDATA%\Lockheed Martin\Prepar3D v2

%LOCALAPPDATA%\Lockheed Martin\Prepar3D v2

%APPDATA%\Lockheed Martin\Prepar3D v2

%USERPROFILE%\Documents\Prepar3D v2 Files[/b]

[i]Copy and paste each of the above paths into the [b]Run..[/b] > [b]Open:[/b] field for instant navigation to these folders.[/i]

[b]4..[/b] Delete those same original 4 folders

[b]5..[/b] If necessary, update your graphics drivers. This becomes important later when the 'shaders' folder content is recompiled at first run of the simulator.

[b]6..[/b] If possible, temporarily disable your antivirus/anti-spyware/anti-malware protection. Again probably unnecessary, but helps to avoid any hold ups.


[b][u]RUN the Patch Updater file:[/u]


[u]AFTER[/u] verifying the [b]MD5 Checksum[/b] to confirm you have a good download: [b][/b]

The location is not critical as it will be looking for an existing '[b]Prepar3D v2[/b]' folder and the path is described in the System Registry. Your newly created temporary empty 'dummy' folder serves the purpose very nicely.

[b]You will see the following messages in order of appearance:[/b]

-Computing Space Requirements (this completed quite quickly in my case)
-Validating install
-Updating component registration
-Copying new files (progress bar very slow and, in fact, appears to halt early on)

-"Could not write value Complete to key..." ( yes, I'm afraid so, don't worry - just click 'Ignore')

-"Prepar3D was unable to load some program files and will now exit.
Please reinstall Prepar3D to restore or repair the program installation"

This somewhat cryptic message doesn't appear to prevent a successful conclusion. 'Prepar3D.cfg' appears to be the only file missing. However, it is an empty file and, in any case, is created and/or populated at first run of the simulator.

Click '[b]OK[/b]' and the Patch will finish.

[b]Edit:[/b] [i]Took approximately 8 minutes to complete. The 'Validation' part lasted longer on subsequent runs - approximately 5 minutes.

I have now run the Patch Updater 3 times with exactly the same file and folder creation results.

Navigate to the temporary 'dummy' [b]Prepar3D v2[/b] folder created in Step 2.
It should now be populated with 117 Files and 15 Folders:


To break it down without specifically mentioning file names:

[b]Prepar3D v2[/b] root folder should contain [u]69[/u] Files and [u]6[/u] Folders. 68 Files have the date modified 24/09/2014 and 1 file 18/09/2014.

1. [b]Addon Scenery[/b] contains a [u]Scenery[/u] and a [u]Texture[/u] folder. Both are empty.
2. [b]Flights folder[/b] contains an [u]other[/u] folder. 2 files are present in this folder. Each file has the date modified 22/09/2014.
3. [b]gauges[/b] contains 36 files all with the date modified 24/09/2014.
4. [b]propdefs[/b] contains 1 file with the date modified 18/09/2014.
5. [b]scenery[/b] contains 2 sub-folders:

[b]0100[/b] - which has 1 sub-folder: [u]scenery[/u] containing 1 file dated 18/09/2014
[b]Global[/b] - has 2 sub-folders: [u]scenery[/u] folder with 1 file dated 18/09/2014 and [u]texture[/u] also with 1 file dated 18/09/2014.

6. [b]ShadersHLSL[/b] contains 5 files and 1 Sub-folder: [u]PostProcess[/u] containing 1 file. All files were modified on 18/09/2014.



Everything matches with the Academic version apart from the following exception:

The folder [b]Addon Scenery[/b] and its 2 empty sub-folders are absent from the Pro Patch Update.

My thanks goes to '[b]jcwunder[/b]' for this helpful information.


[b]7..[/b] As a precaution, I would create a copy of the temporary 'dummy' [b]Prepar3D v2[/b] folder with the patch files and folder content and overwrite all these files with copies from your original Prepar3D v2 installation which still exists in the '[b]xxxxxx[/b]' folder. This will allow you to recover your v2.3 installation should this update not work for you. Hopefully it won't be needed and can be deleted later.

[b]8..[/b] You now have 2 options:

a) Perform a multiple selection (Files and Folders) of the entire content of the temporary 'dummy' [b]Prepar3D v2[/b] folder and [u]merge[/u] it with the existing content of your v2.3 '[b]xxxxxx[/b]' folder.


b) You can take your time and copy and paste files folder by folder.

[b]9..[/b] Move the temporary 'dummy' [b]Prepar3D v2[/b] to a safe location in case it is needed again - unlikely, but you never know!

Now [b]RENAME[/b] the '[b]xxxxxx[/b]' folder back to [b]Prepar3D v2[/b]

[b]10..[/b] Reboot your computer. Not essential, but ensures a fresh start.

[b]11..[/b] [i][b]RUN...... Prepar3D[/b][/i]

Be patient as it will take some time to rebuild and load everything at the first run. If successful you will find yourself sitting in the F-35A Lightning II.

Check the version number and it should now be displayed as:

Prepar3D Version 2.4.11570.0
Simconnect Version

Run and test a few times before restoring all the 3rd Party content which, of course, is still in place, but not yet functional. Before doing so, check with the Developers as to whether updates have been issued to ensure ongoing compatibility of their products with Prepar3D v2.4. [b]Skip this step if you have not installed any Addons[/b]

Update FSUIPC if you need it and require it to be functional in Prepar3D v2.4

Remember those folders which were backed up in Step 3? They contain everything (including the file Scenery.cfg) you might need when it comes to, for example, comparing/updating new file (v2.4) content with old (v2.3).

[b]Restore[/b] your old [b]Scenery.cfg[/b] file AFTER backing up the newly generated v2.4 file.

[u]Restore[/b] the [b]dll.xml[/b] and [b]exe.xml[/b] files to their original locations. Some Addons may have written entries to these files and will not work unless these are in place and correct. Note they may not yet be present in the 2.4 updated installation nor, indeed, in your v2.3 installation if you have not installed any Addons that require them.[/u]

[u]THEN install any 3rd Party Product updates, if required.[/u]

[b]12..[/b] [b][i]RUN.... Prepar3D[/i][/b] (Again, be patient as it will have to rebuild the scenery indexes and update the database before beginning the loading phase.)

Good luck! Hopefully you won't be needing it!


[b]Edit:[/b] I cannot say what impact, if any, patching in this way will have on future Patch Updates. It may be that you would have to stick with this method until a version comes along where a full reinstall of Prepar3D would be deemed to be desirable. Pre-existing entries in the System Registry did not cause this Patch Updater to fatally abort. Hopefully this procedure will continue to work unless, of course, LM change the Patch Updater's behaviour in the future to ensure a successful outcome in every case. That is out of our hands.

[b]Edit (09/10/2014):[/b] few minor changes to the text to clarify some points. Nothing critical has been changed.

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