Installing on the New PC

The installer is one window. It checks itself, shows you where it will install and everything it will set up, and installs only when you click Install. This page goes through it from top to bottom, using the words on the screen.

• Copy the whole installer. If the build gave you a .wamdata file as well as the .exe, copy both into the same folder, and keep their names. See Big apps.
• Only run installers you trust. An installer runs with full administrator rights. Treat one like any other program: run it only if you built it, or got it from someone you trust. See Privacy and security.
• You need administrator rights on this PC, and Direct3D 12 for the window. Without Direct3D 12 you can still install from a command prompt. See Command line.

Double-click the installer. Windows shows the UAC prompt. An installer is not signed unless whoever built it signed it, so the prompt usually says Unknown publisher. That is expected. See Privacy and security.

The window, "WinAppMigrator Installer", "Reinstalls an application captured on another PC", opens at once, however big the installer is. It says "Checking the installer…" while it checks the hash of its whole package. That reads all of it, so a big installer takes a while. From this moment the installer holds its own file open, and its data file if it has one, so neither can be changed or swapped while the window is up.

The check can stop here, with a red message. The common ones are:

• The installer is damaged or was changed after it was built: copy it again from where it was built.
• Its data file is missing, or is not the right one: copy both files again, into one folder.
• "This installer's package cannot be used on this PC", for example because the app's programs are built for another kind of processor, or need a newer Windows. Nothing has been changed.

All of these are explained in Troubleshooting.

When the check passes, the window's title becomes "Install" and the app's name.

The first card has the app's name, with the publisher and version under it, such as "Fabrikam Inc. · 1.7.3". Then:

The publisher name on the first line comes from the package, so anyone could have written it. The Installer row comes from Windows, and is the one to trust.

If the folder in Install Location cannot be used, a hint under it says "Enter another folder, such as C:\Program Files\App:" and why. Install and Preview Changes stay greyed out until you choose another. The reasons are:

If the folder has files and an earlier install of this project is on record there, the installer will use it, and warns: "This folder already has files. Files with the same names are replaced, and come back if you uninstall."

Once a folder is accepted, the window replaces a file, registry value, service, task, shortcut, or variable of the same name, as --force does on the command line. What already belongs to another app, such as its service or file type, still stays that app's.

If the drive looks short of room, an amber note says "There may not be enough room here" and what is needed. The package can be unpacked on another drive, but the app's files still have to fit on this one. The install itself checks the room again before it starts.

If a previous install by any of these installers was cut off, by a crash or a power cut, an amber note says "An earlier install of" that app "never finished. Install undoes it first." That happens automatically when you click Install.

This card is the list you agree to when you click Install. Under its title it says:

All of this is done with administrator rights. If the install fails, what it changed is put back, and you are told of anything that could not be. You can also undo the install later from Settings, under Installed apps. Files it replaces come back, and runtimes it installs stay.

Each row has a name, a label at the right saying what kind of thing it is, and a line saying what it does. A label in the usual blue is ordinary. A label in amber marks something that runs with full rights, such as a service that runs as LocalSystem, a driver, or a firewall rule that lets connections in. Look at those twice.

If the list is empty, it says "Nothing: it only copies files, and settings in the app's own registry keys."

The list is worked out for the location in the box. If you change the location, it says "Working out what this would set up at this location…" for a moment, and Install waits.

Some things can only be judged once the install gets to them, such as a service of the same name that already belongs to another app. Those stay on the list as asked for. When the install gets there it leaves them alone, and says so.

Under the rows, amber notes say what you ought to know, for example:

• that credentials were not put in the installer, so you may have to enter them again;
• that the License or User Data option was off when it was built, so that data is not in it;
• which certificates the app seemed to rely on, which are never installed;
• what whoever built the installer left out, and what they added;
• that the app may not work here: "This app was on Windows build" a newer one, or that Windows would run some of its programs "through an emulator";
• that files from Documents or Saved Games will go "under" the install folder "in a folder named _external", because this PC's folder is outside your profile.

Then, in amber, each thing the safety rules leave out, with the reason. The first 20 are shown in full. The rest are under "more were left out", which you can open. The rest of the install still goes ahead without them. What is refused, and why, is in What goes in an installer.

If the package cannot go to the chosen location at all, a red message says "This package cannot go to this location" and why.

This card only appears when the installer holds user data or license data. Each box starts ticked.

Changing a box changes the list above to match, straight away.

User data always goes to whoever is signed in to Windows, even if another administrator's name was typed at the UAC prompt. If the installer cannot tell who that is, it says so, leaves per-user settings out, and puts user data under the install folder rather than guess. If no one is signed in to that session, user data and per-user settings go to the account the installer runs as, and it says that too.

"What this app needs, and how each is provided." Each runtime has a label:

If there are none, it says "No additional runtime dependencies were detected." See Runtimes.

Preview Changes works out exactly what an install would do, and changes nothing. It checks there is room, unpacks the package to a private folder, works out the changes, and removes that folder again. The result card is headed "Preview: Nothing Has Been Changed Yet", with Changes Planned, and a list of the changes, with services, tasks, and shortcuts first. The window lists the first 300, then says how many more.

A preview does not check each file's hash. The whole package's hash was checked when the window opened.

Install stays greyed out until the location can be used and the list is for that location. When you click it:

1. It works out the list once more. If what it would do has changed since you looked, it installs nothing, shows the new list, and says "What this would do here has changed, so nothing was installed. Look over the list below, and click Install again if it is what you want."
2. It checks there is room on every drive it writes to.
3. It unpacks the package to a folder only administrators can use, checking each file's hash as it comes out.
4. It installs, keeping a journal of each change first, so that it can be undone.
5. It reads back every file it installed and checks its hash.
6. It starts the services that are set to start by themselves.

At the bottom you see what it is doing, a count where there is one, the time it has taken, a progress bar, and Cancel. The steps you may see are "Getting ready…", "Unpacking", "Checking the package", "Undoing an earlier install that never finished", "Installing runtimes", "Copying files", "Setting up services", "Setting up drivers", "Writing registry settings", "Restoring license data", "Setting up scheduled tasks", "Making shortcuts", "Setting environment variables", "Adding the app to Settings", and "Checking what was installed".

Cancel shows "Cancelling after the current step…", and then "Putting back what was changed". Closing the window while it installs does the same as Cancel: the window stays until everything is put back. If nothing had been changed yet, it says "Cancelled. Nothing was changed."

The installer checks hashes three times:

1. When the window opens: the hash of the whole package. A truncated copy, or one edited after it was built, is refused before anything in it is read.
2. As it unpacks: each file's hash, before anything is written to its place.
3. After it installs: it reads back each file it installed and checks it again.

Hashes catch damage, and changes by anyone who does not also update the hashes. They do not prove who made an installer. Only a signature does that.

The result card appears at the top, headed "Install Result".

Then three tiles: Changes Made (or Changes Put Back after a failure), Warnings, and Errors. Labels say Package Hashes Valid and Installed Files Valid, or INVALID in red. Up to five warnings and every error are shown as messages. "A dependency needs a reboot to finish. Restart Windows, then launch the app." means a runtime asked for a restart.

Changes, with a count, opens the list of what was done, up to 300. If the install did not finish cleanly, the path of its log is shown as Log.

After a clean install, the buttons at the bottom become Close and Open Install Folder.

• Program files go in the install location.
• User Data, with that box ticked, goes to the signed-in account's own AppData, Documents, Saved Games, and to ProgramData. A Documents or Saved Games folder that this PC keeps outside your profile is not written to. Those files go under the install location, in _external, and the list says so first. With the box unticked, all user data goes under the install location.
• Shortcuts go to this PC's Desktop and Start menu: yours, or everyone's if that is where they were.
• Path gets only the app's entries added. Nothing else in it changes.
• What another app already has here stays that app's. A file type, link type, COM class, service, event log source, font, or anything like it that already belongs to something else is left alone, and the installer says so. An app that expected to open http links, for example, has to be set as the default again in Settings.
• Settings gets an entry for the app, so you can uninstall it like any other. See Undoing an install.

More are in Troubleshooting.

Last changed 2026-11-11. Describes WinAppMigrator as of its latest release, 0.6.0.