After the download: now what?

If you haven't downloaded anything yet, start with the universal downgrade guide — it covers finding the IDs and building the command. This page picks up the moment DepotDownloader prints its summary and exits, leaving you staring at a folder. That folder is a complete copy of the game's files at the version you asked for; the job now is just to put it where something can run it.

01The output folder, decoded

Where the files landed depends on whether you passed -dir:

• With -dir .\my-folder — the game files are written straight into my-folder, merged across every depot you requested. This is the tidy case, and the reason every guide on this site uses -dir.
• Without -dir — DepotDownloader creates a depots\ folder next to itself, with a subfolder per depot ID (depots\441\, depots\232251\, …). If you downloaded several depots, the actual game is the combination of those subfolders' contents.

Inside, you'll see a folder named .DepotDownloader (sometimes one per depot). That's not part of the game — it's the tool's own bookkeeping (the manifest cache and the resume data it writes during download). You can ignore or delete it. If a download was interrupted, leaving it in place lets you re-run the exact same command to resume where it stopped rather than starting over; once you're done, it's just clutter.

So the mental model is simple: strip the .DepotDownloader bookkeeping, and what remains is the game's files — the same files Steam would have put in steamapps\common. Everything below is about where to move them.

02Three ways to use it

There's no single right answer — it depends on what you want. Pick the row that matches your goal:

03A · Run it where it sits

The lightest option, and the one this site recommends for experiments: leave the downloaded folder where it is and launch the game's executable directly. Your real Steam install stays current and untouched beside it, and you can keep as many version folders as you like.

1. Open the folder and find the game's .exe (e.g. hl2.exe, Risk of Rain 2.exe, SkyrimSE.exe). Double-click it, or make a desktop shortcut.
2. Keep Steam running and logged in — most games still talk to Steam for ownership and friends even when launched this way.
3. If the game flickers and then the current version starts instead, it uses Steam's restart DRM (SteamAPI_RestartAppIfNecessary). The fix is a one-line text file: create steam_appid.txt next to the exe containing just the AppID (e.g. 550), then launch the exe again. This is the same trick the PAYDAY 2 and Left 4 Dead 2 guides use.

Standalone is ideal for speedrunning, modded experiments, and "I just want to see the old build" — nothing about your Steam library changes.

04B · Copy it over your Steam install

When the old build is the version you want to live in — a modded playthrough, a server, a long save — replace the files in your Steam install with the downloaded ones.

1. Find the install at steamapps\common\<Game> (Steam → game → Properties → Installed Files → Browse opens it).
2. Copy the downloaded files over it, replacing when prompted. (If you downloaded without -dir, merge each depots\<id>\ subfolder's contents into the install.)
3. Stop Steam from updating you back: Properties → Updates → "Only update this game when I launch it". Steam offers no true "never," so add the community's enforcement trick — set appmanifest_<appid>.acf (in steamapps\) to read-only via its file Properties, so Steam can't rewrite the manifest to schedule an update. This is the same pair the Skyrim guide uses; untick read-only the day you want to move forward.
4. Launch through Steam as normal — or, if Steam keeps pulling you forward anyway, launch the exe directly per option A.

05C · Make Steam fully adopt it

Sometimes you want Steam itself to believe the game is properly installed at this version — listed in the library, launchable from the Play button, no "missing files." That's controlled by the game's app manifest, a small text file Steam keeps for every installed game: steamapps\appmanifest_<appid>.acf. (Note: this appmanifest_*.acf is Steam's install record — a completely different thing from the depot manifest IDs you fed DepotDownloader. Same word, unrelated jobs.)

The field that matters is StateFlags: StateFlags "4" means "fully installed" — up to date and playable. To make Steam adopt a manually-placed build:

1. Exit Steam completely first — it caches the .acf in memory and will overwrite your edits if it's running.
2. Make sure the files are in steamapps\common\<installdir>, where <installdir> matches the "installdir" value in the .acf.
3. Open appmanifest_<appid>.acf in a text editor and set "StateFlags" "4". If you don't have an .acf at all (you downloaded outside Steam entirely), you can generate one — a minimal .acf needs appid, Universe "1", installdir, and StateFlags "4"; the community tool steam-appmanifest writes these for you.
4. Start Steam. The game should show as installed at your version.

One honest caveat: Steam can still schedule an update over a StateFlags-4 game it thinks is outdated, which is why this is best combined with the option-B pair — "only update on launch" plus a read-only .acf. Even then, enforcement isn't perfect across every Steam client version; if absolute stability matters, option A (standalone, Steam never knows) is the surest. Adoption is the nicest-feeling route, not the most bulletproof one.

06Keeping your saves

Before you overwrite or switch versions, know where your saves live — it varies, and getting it wrong is the one mistake that costs something irreplaceable:

• Outside the install folder (most modern games) — under Documents\, %APPDATA%\, or %LOCALAPPDATA%Low\ (e.g. Documents\My Games\, AppData\LocalLow\<studio>\). Overwriting the install doesn't touch these, but a newer save may not load on an older build — back the save folder up anyway.
• Inside the install folder (some games — Kerbal Space Program, Subnautica's SNAppData, Factorio if portable) — here overwriting the install can hit your saves, so copy them out first.

And turn off Steam Cloud for the game while you're living on an old version, or cloud sync will keep pushing newer save data at a build that may not understand it. Each game guide on this site names that game's exact save path; when in doubt, back up both the install folder and the likely user-data folder.

07If it still runs the current version

The classic frustration: everything copied correctly, but launching still starts the latest build. Three causes, in order of likelihood:

1. Steam quietly updated it. Check the game isn't mid-update or already patched; re-apply "only update on launch" + read-only .acf, then re-copy the old files.
2. Restart DRM. The exe relaunched the library version via SteamAPI_RestartAppIfNecessary — use the steam_appid.txt fix from option A and launch the exe directly.
3. Launcher interposition. Some games boot through their own launcher (Rockstar, Paradox, Bethesda) that "repairs" old builds forward — those have game-specific flags (an offline mode, a no-update argument); the relevant per-game guide covers it.

Each of these — and the steam_appid.txt mechanism in depth — has its own diagnostic on it still launches the current version if you need to dig in.

To return to the present whenever you're done: untick the read-only flag on the .acf, set updates back to automatic (or just hit Update), and let Steam pull the current build — or "Verify integrity of game files," which restores you to live. Nothing here is permanent; the worst case is a redownload.