P3DV4 install location - does it matter anymore?

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Is the philosophy still the same- to install to some location outside the Program Files folder- or have Lockheed Martin and Microsoft resolved their differences? Why does LM have the default location as C:\program files  even if they might not want it there?

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As far as I have seen, keep the flight sim and other related programs out of the Program Files or Program Files(86) to keep from having problems.

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Yeah, not unless you plan on spending roughly an hour redoing your security settings for the Program Files folders. Steam beat the issue for FSX, but LM didn't. Most people I know just put it in the root directory.

Best wishes.


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As far as folder goes - you are much better off NOT putting it into the ProgramFiles(x86) folder. Ideally, if you have it putting P3D on it's own drive is the way to go. Depending on your setup and drive size, you typically do NOT want it on the C drive unless you have no choice.  But definitely put it into it's own folder, like D:\P3D.


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The real story is that it only takes 15 seconds to add Modify permission to the Users group on:

C:\Program Files\Lockheed Martin\Prepar3D v4


C:\Program Files (x86)\Lockheed Martin\Prepar3D v3

and even FSX.

After that, any app that installed its read/write data there (e.g. PMDG) or any logged on User can run any apps like Notepad and edit files.

Other than that there's no issues.


FSX:SE is a bity of an anomaly, because it force runs up with Admin Privileges so that it Acquires Modify permissions. So why if the SteamApps folders already have the Modify permission granted to the Users group as Dave correctly says? Because the Users group does not have access to the C:\ProgramData\Microsoft\FSX-SE folder for the setting of scenery.


So in short; if the problem is simply the Users group not having Modify permission on a folder - Instead of making a new folder to gain permission by being the owner, grant the permission to the group that uses it.

Note also that being the sole owner of a folder that we subsequently install software for All Users onto can make things totally unusable leading to stuff like Taking Ownership, Running as Admin, totally unnecessary setting of UAC slider lower and so on and so forth.




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A little more clarity on that:

Historically way back when we had WinXP regular Users had write permission for the program files folders. Plenty of addon installers placed files and folders handily in the FS folder. Here's the issue; some installed with the intention of their addon writing updates to these files, like situation data whatever rights the User had.

The regular logged on user would be running the sim and an addon would update its files during or after the flight. There were no issues back then because they had permission - even though the files are in a read-only folder.

Unfortunately later versions of Windows removed the Modify (Write) permissions for the regular users on those folders. It is often deemed simpler to make one's own folder, or Run as Admin, thus acquiring the necessary permissions, but it's nice to know what the real issues are.

So in fact the sim really does install correctly into Program Files, Windows really does operate correctly in terms of Permissions and Privileges, so everything is perfectly good.

Remember that there are only issues if we want to update files in a folder that is read-only to a regular user. So it's an unfortunate historical issue with the way some addons install and operate and we can use these three workarounds:

1. Run Everything as Admin

2. Install into a custom folder

3. Set the Modify permission for the Users


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OK let's have a closer look at those three options:


1. Run Everything as Admin:

Due to the way some apps work and inter-operate, all apps need to be at the same privilege level, and so usually if one item, say the sim, is run as admin, all addons should be run as admin as well, otherwise there can be unexpected results and failed communications, depending on what those apps do.

Also Run Everything as Admin comes with the obvious possibility of acquiring some kind of malware or virus activity, and being really surprised one day to discover having purchased someone else's underpants, or worse.

On top of that, Admin Privileges are Acquired by installers and settings makers when we run them, they usually need not be additionally set in the shortcut or right-clicked to Run as Admin, that may actually present an error in some apps.

Installer and system setting Apps might actually have to Acquire the necessary Privileges when we run them, only certain tools may require setting to Run as Admin in the shortcut.

An app or file might become infected so when the app is run at first without Admin Privileges it has then checked itself for tampering before going to Admin and so setting the shortcut to Run as Admin Is actually a mistake.

There are situations for example universities or professional firms whereby an Admin must be called to type in the Password when they want to Run something as Admin. Since that can't be going on all day with regular User mode apps, an app might need to be installed with necessary permissions in a professional environment or it is useless. Running regular apps as Admin is basically unprofessional.


2. Install into a custom folder:

Nothing wrong at all with that. Can't be avoided if we want to install to a separate drive to the O/S drive. Remember that the operating files of the sim all reside on the O/S drive for performance reasons. Installing into another drive may seem like spreading the sim across drives could be a worry to performance but more or less it's not. However, the sim will operate at the performance of the slower drive when accessing uncached data.

Beware, we also might want to set the Modify permission for Users of any apps installed on custom folders as only we own them, not all installers work the same.


3. Set the Modify permission for the Users:

If we install to the regular application installer-led folder location, we need only set that permission before installing addons if we run FSX or P3D. We can still install our 500Gb photo-scenery collection onto another drive, or offload some aircraft, it's just a matter of setting the configs.



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The Decision to Install to the Primary Drive or Install to a Different Drive

One thing you may wish to consider is making an Clone of your installation so that if you, a Windows or other software update, or an addon install ever mucks things up you can go right to the image and fly right away.  Of course it also serves as a pristine backup for you.  Think of it as an image that you can run off of.

Unless you have many hard drives (and one very large one - atleast 2GB but likely 3GB - to create the clone or image to), it would be necessary to have P3DV4 installed on our C drive so that it gets cloned along with your registry.  I say that, but there may be some tools that would include folders/files from another drive in the clone - I just don't know if there is.

I've longed used a TERRIFIC program called Macrium Reflect (which is free for home use) to make images and clones of my drives.  Macrium can include other drives in an Image, but I don't think it will include them in a clone.

Now, you do eek out a little more performance by having P3DV4 on a different drive than your operating system, but if you don't need that small amount of performance increase then for my money having the Clone or an image is more important.  Note though, I've only had one occaision to have to result to either an Clone or an Image, but I'm really happy I had it when I did as we all know what having to reinstall is like - better than it used to be, but still a time consulting pain!

There is another positive about Macrium that I'm forgetting, but needless to say I love the program - even over similar and better known payware software.  I've setup several people with clones, and the confidence it gives us is really worth it as we run countless addons for flight sim.... but remember, it's backing up a lot more than flight sim, so all your other important installations and files are protected as well.  Priceless for me, especially given the wide range of flight sim betas I do!!!

I hope this is helpful to everyone.

My very best wishes for happy flights!



Ah, I just remembered the other positive!  Macrium Reflect can create and save a Clone to a different size hard drive!  I don't know if any other similar software will do this, but back when I was looking at similar software (years ago) they didn't.  Of course this also works with SSDs to non-SSDs and the other way around.  It's a TREMENDOUS FEATURE!


Edited by DaveCT2003
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21 minutes ago, SteveW said:

OK let's have a closer look at those three options:

EXCELLENT info as usual Steve.


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Hi Dave,

Yes the issue of the backup is a bit of a worry for some and those backup imagers are great especially when we consider complications of the registry and the way some files are spread amongst drives. I would check out Daves recommendation.

Of course I've got to have a different option: RAID10. Four 2Tb drives, two striped for speed, and a pair mirroring those becomes a 4Tb drive C:\. If any drive becomes suspect or fails I can swap it out and when it boots up it rebuilds the array. I tend to do backups in a different way and keep a copy of important folders on portable drives and offsite.

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As a developer, I have a different set of priorities for my software installations. Since a great many of the FSX/P3D developer tools are still "command line" based, having the shortest paths possible is a definite plus! Thus

C: - OS only





In addition, since I have six computers currently on my LAN, granting full sharing privileges becomes a more manageable task as well.

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In the old days we cringed when customers wanted to partition the drive into C: D: and E: for example D = accounts and E = marketing. In those days a 500Mb drive partitioned like that might start thrashing and prove unreliable. Since virtualised FAT that's not an issue these days. Something like:



 was better and all they needed to backup  was C:\CO. That still holds well today and it's what I do basically.

As far as pathname lengths are concerned I'm largely unaware since they are nearly always copy pasted from Explorer into scripts and bats if I have to do anything more than once.



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Yup - having to continually type "C:\ProgramFiles(x86)\LockheedMartin\Prepar3D V4\Prepar3d.exe

could be a pain.   Actually it's one of the main reasons I have a dedicated sim drive - F:\P3D - much easier to deal with.:biggrin:



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Paths are just like URLs it doesn't matter how long they are - no one types them, or paths, anymore... :biggrin:


A few of us had a chat about how this subject main issue: 'must we use an alternative folder' became so confusing and what to do to rectify the situation did not become apparent. One pointed out that since P3D encourages devs to avoid placing read-write files into the Program Files folder there's no need to provide permission to Modify it, (or at least in the future) and so we would need not avoid installing to default location Program Files to gain permission that way. This of course is no different to FSX, the actual difference is that addons installed files there expecting the User has write permission.

Still leaves the issue wide open. If you suspect you may want to edit files at a later date or perhaps install addons and they put read-write files there, then maybe think about installing to a custom folder or applying the permission whichever is easiest or most appropriate. If you do install to the default location and later come across an issue with an addon there or want to edit something - add the permission then.



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