I've got 100 games and want to reinstall Windows

[MSXCF]

Will I have to download everything again? Almost all games are on the D drive.

I have Windows 8.1 Home (on the C drive), and I have 100 Steam games, almost all games are installed on the D drive.

This PC came with Win 8 Home OEM, but I want to install Windows 7 as I have an unused DVD with Win7 Ultimate.

I recently tested Win10, before I downgraded to 8.1 again. I'm not sure but I believe all my games still work (they were installed before I tested Win10).
But I can probably not downgrade to Win7 without formatting, and if I format the system disk then I will of course have to reinstall all the games.

I have a fast Internet connection, but it still takes a lot of time to install that many games, with all their extras (DLC etc), especially if I have to download everything again.

But will I have to download all the games again? What is the best way to proceed?

Thanks :)

[JK]

You probably will, or you can buy/use an external HDD and store your games on there untill you have formatted the other HDD. When a HDD formats, you'll lose everything, so that's the best solution I can think of :).

[The Giving One]

Save the steamapps folder to a safe location. Install Steam on the new drive/computer when you get it all set up. Move the steamapps folder back to its default location and all that perhaps may be needed it verifying some game files for some games.

https://support.steampowered.com/kb_article.php?ref=2037-QEUH-3335

The steamapps folder is the key. Copy/move/backup the entire steamapps folder. Then, you don't have to redownload any games again.

[Overloader]

You can format the C:/ drive only and install Win7 on it.(Maybe unplug the D:/ drive before, so only c:/ gets formated and nothing is deleted by accident)
When all Drivers,Programms and Steam are installed you go to Steam:

1. Click on Steam(left upper Corner)
2. Open Settings
3. Go to Downloads
4. Click on Librarys
5. Click on "Add Library"
6. Select the old folder on your unformatted D:/ drive
7. Close the Settings and go to your Game overview
8. Smile while you see all your games from your D:/ being recognized and still playable(maybe they need to reinstall when started for the first time on the new system)

I hope i could help. I tried to translate everything into english as good as possible. ;)
MfG Overloader

[MSXCF]

Originally posted by SnowyJesse:

You probably will, or you can buy/use an external HDD and store your games on there untill you have formatted the other HDD. When a HDD formats, you'll lose everything, so that's the best solution I can think of :).

Thanks for the reply.

How will an external drive help me? I'll not format the D drive where the games are installed. They are there and will not be deleted, but I don't know if I still will have to download them when I reinstall them. I guess Windows won't know they are on the D drive.

[The Giving One]

Originally posted by MSXCF:

Thanks for the reply.

How will an external drive help me?

Put the steamapps folder in the external drive and disconnect it. Format and reinstall Windows and get all drivers and Windows itself updated. Install Steam, get the code from your email that authorizes Steam to be used on that new installation of Windows, then put the steamapps folder back in the Steam folder after you get Steam installed.

No need to make other libraries and all that mess.

[The Giving One]

You need to be sure drivers are available for your hardware if you are going to reinstall the OS. Do that from the official manufacturer's website and not just simply by using Windows update.

Official drivers from official manufacturer only.

[MSXCF]

Thanks for the replies everybody.
I hope nobody missed the fact that almost all games are on the D drive, but I have edited my opening post so this becomes clear already in the first line (if anyone skipped the second line).

Originally posted by The Giving One:

Originally posted by MSXCF:

Thanks for the reply.

How will an external drive help me?

Put the steamapps folder in the external drive and disconnect it. Format and reinstall Windows and get all drivers and Windows itself updated. Install Steam, get the code from your email that authorizes Steam to be used on that new installation of Windows, then put the steamapps folder back in the Steam folder after you get Steam installed.

No need to make other libraries and all that mess.

I can do that for my one single game that is on the C drive, it's a big 50 GB game. But my biggest concern are the 99 games on the D drive, they are almost 600 GB.
The D drive is internal and not so easy to disconnect (it's a laptop), but I don't see how installing Windows on C can possibly wipe the D drive.

I will install Steam and log in with username and password.... there's no need to authorize Steam to be used on a new Windows installation? Well, if it is required I'll just follow instructions.

I'm aware I have to download all the drivers for Win7, and I have verified that it'll work on my Asus laptop.

[The Giving One]

Yes, changing hardware in your computer can and almost surely will make Steam see it as a "new device", so you will have to reauthorize that computer when you install Steam on it and try to log into your account.

Especially when reinstalling the OS.

What is the one game you have on the C drive ? I think you may be misunderstanding what I am suggesting.

You asked how an external drive will help you and I answered that. Use the external drive to save the steamapps folder on. Disconnect it. Follow everything else I said.

Again, if you save your steamapps folder, you don't have to download your games again.

Is Steam installed on C or D ?

[The Giving One]

Originally posted by Patrick:

Originally posted by The Giving One:

Save the steamapps folder to a safe location.

Just a note.

I also save the userdata folder too, for created and linked custom non game Steam Grid images, screen shots taken saved, and organized and categorized large Steam Library.
Shortcut.vdf and Steam controller configs are int there also

You are right, and of course the saves that are sometimes stored in documents or "my games" . But OP was only asking about redownloading all the games, so I did not go into all that detail here. That is a whole other animal to explain, and if OP wishes, he can get into that if he or she wishes.

Thanks for the comment and clarification. Much appreciated.

[MSXCF]

Originally posted by The Giving One:

What is the one game you have on the C drive ? I think you may be misunderstanding what I am suggesting.

You asked how an external drive will help you and I answered that. Use the external drive to save the steamapps folder on. Disconnect it. Follow everything else I said.

Again, if you save your steamapps folder, you don't have to download your games again.

Is Steam installed on C or D ?

I have The Secret World (MMORPG) on the C drive.
Steam is installed on the D drive. I have a Steam library on both drives.

[The Giving One]

The .acf file for The Secret World shoud be 215280.

Most of your game folders should be in your common folder, located inside your steamapps folder on D.

So you should have that .acf file in your actual steamapps folder. If you do, then you could just move the steamapps folder to the external drive, then move the The Secret World game folder from the C drive to the common folder that is inside the steamapps folder that you just moved.

Now all your game folders are in the common folder where they belong, in one nice neat location.

In short, place ALL game folders inside the common folder, and be sure all .acf files are in the steamapps folder. Save the steamapps folder.

If you don't save the .acf for The Secret World, then you will have to redownload it when you reinstall Steam on the new installation of the OS.

That goes for ANY Steam games. The .acf files are the files that let Steam "see" your games as installed.

Then, you may only have to verify the game files for any games you have issues with as linked above.

So, game folders inside the steamapps/common folder, and .acf files inside the steamapps folder. Save/move/backup the steamapps folder to a safe place.

[MSXCF]

Originally posted by The Giving One:

You asked how an external drive will help you and I answered that. Use the external drive to save the steamapps folder on. Disconnect it. Follow everything else I said.

I do have an exernal USB hard disk, but it's nearly full of backups already. I can't move my Steam library there.
The only option I have, is the internal D drive in the laptop. It is a separate drive and not a partition on the system drive, so it should work as well as an external disk?
I will not format the D drive by accident. Installing Windows on C will not wipe the D drive?

Originally posted by The Giving One:

So you should have that .acf file in your actual steamapps folder. If you do, then you could just move the steamapps folder to the external drive, then move the The Secret World game folder from the C drive to the common folder that is inside the steamapps folder that you just moved.

So I should secure only the \steamapps folders and not the \Steam (parent) folders?
C:\Steam\steamapps
D:\Games\Steam\SteamApps

I used to have The Secret World on the D drive, but I moved it to C. The reason I have TSW (and The Park, a TSW spin-off game) installed on the C drive, is that C is a SSD and I wanted to make TSW load data as fast as possible. I'm unsure how much it helped though, because much of the data comes from the game server.

A second reason to put the mammoth on the C drive, is that TSW (45.5 GB) + The Park (2.7 GB) saves 48 GB disk space on the D drive. The D drive is a 1TB 7200 rpm HDD and it's about 70% full without those two games. It's too full already.

Originally posted by The Giving One:

The .acf files are the files that let Steam "see" your games as installed.

Thanks, I didn't know that. :)

[The Giving One]

You said "steamapps folders" as in plural. Do you not only have one steamapps folder there ? Or do you really have two of them ?

You made no mention of my commets about the .acf files either, except for the one above. Just want to be sure you understand and that is why I am asking here if you do , please. Thanks.

[MSXCF]

(Edited)

Originally posted by The Giving One:

You said "steamapps folders" as in plural. Do you not only have one steamapps folder there ? Or do you really have two of them ?

You made no mention of my commets about the .acf files either, except for the one above. Just want to be sure you understand and that is why I am asking here if you do , please. Thanks.

There is a "steamapps" folder on each drive. I've got 2 games on C, so naturally there is a steamapps folder there also. :)

I did not mention the .acf files because you explained them so well. I understand their importance.

[The Giving One]

Originally posted by MSXCF:

There is a "steamapps" folder on each drive. I've got 2 games on C, so naturally there is a steamapps folder there also. :)

Very well. Then save both of them or just keep one steamapps folder and place the files and folders that are inside the other one into that one. In other words, you should be able to merge them together and save them on a backup media such as USB or external hard drive.

Be sure that media is NOT connected to your computer when you reinstall Windows though.

Then you put it back into its default location once you get Steam reinstalled after the Windows reinstallation.

And finally, maybe just have to verify the game files for some games if you have issues with them.

What about my post earlier concerning what OS you are going to install ?
http://steamcommunity.com/discussions/forum/1/358415206088703383/#c358415206088756311

You do understand that you cannot just install any OS on just any computer, right ?

You do understand about system (not just GPU) drivers, right ?