Install Ubuntu 3: Complete the Installation and Verify First Boot

Continue the third Ubuntu installation lesson by completing the final installer screens, restarting safely, and verifying that Ubuntu starts correctly.

Scope of this lesson

This is the third installment in an Ubuntu installation sequence. It begins after you have prepared the installation media, started the computer from it, and worked through the earlier installer screens.

Ubuntu is the Linux distribution being installed. The installer is the guided program that copies Ubuntu to the selected storage device and creates the system needed to start it.

Before continuing, confirm that you have:

Started the computer from the bootable Ubuntu installation media.
Selected the intended language, keyboard layout, network option, and installation type where those screens were part of the earlier lesson.
Reviewed the storage or partitioning choice carefully. Disk and partition choices can affect existing files and operating systems.
Created or entered the requested user, computer, and password information if those screens have already appeared.
Reached the installer’s progress or final configuration stage without an unresolved warning.

By the end of this installment, Ubuntu should be fully installed, the installer should be closed, and the computer should successfully start Ubuntu from its installed disk rather than from the installation media.

If you have not yet prepared the media or selected the installation destination, stop here and revisit the earlier parts of the course. For background, see What Is Linux and What Is Partitioning.

Installation stages at a glance

Stage | Required action | Expected result | How to verify

Earlier preparation | Boot from installation media and make the initial installer selections. | The Ubuntu installer is running and the intended installation path is selected. | Review the installer summary and destination before proceeding.

Storage confirmation | Approve the selected disk or partition plan when the installer asks for confirmation. | The installer is authorized to apply the displayed storage changes. | Read the disk summary; do not continue if the destination or data-impact warning is unexpected.

Installation progress | Allow the installer to copy files and configure the system. | A progress indicator advances and the installer reports configuration activity. | Wait for completion messages; do not power off the computer unless it is clearly unresponsive and recovery is necessary.

Final installer screen | Choose the action to finish installation, such as restarting or closing the installer. | The installer reports that Ubuntu is ready to start. | Look for a completion message and follow its restart instruction.

First boot | Remove installation media when requested, then allow the computer to reboot. | The installed Ubuntu system starts. | The boot screen and login or desktop belong to the installed system, not the temporary installer.

Initial checks | Sign in and confirm basic hardware and system operation. | You can use the desktop, open applications, and inspect basic settings. | Check the display, keyboard, mouse or touchpad, storage, network, and shutdown controls.

Complete the remaining installer screens

1. Review the final summary

Before the installer begins or finishes applying changes, review its summary. Confirm the target disk, installation type, user information, and any optional software or network choices. This is the last useful point for detecting an incorrect destination before storage changes are applied.

Storage confirmation is not identical in every Ubuntu release or installation path. Some installers show a separate confirmation screen, while others include confirmation in a summary or warning dialog. Treat any screen that describes disk changes as mandatory to review, even when the button wording differs.

2. Let installation finish

When the installer is copying files or configuring the system, leave the computer connected to power. Avoid closing the installer, pressing reset, or removing the installation media unless the installer explicitly requests it. Progress can pause temporarily while files are verified or configured.

Do not assume that a frozen-looking progress indicator means failure immediately. First check whether the computer still responds, whether storage activity continues, and whether an error or prompt is waiting for input.

3. Handle optional preferences

Optional choices can include downloading updates during installation, installing additional media support, or connecting to a network. These choices may change installation time and available features, but they are not the same as the selections required to define the installation destination and user account.

Mandatory: Resolve installer errors, confirm required storage changes, provide required account information, and accept the final completion action.
Optional: Select additional software, download updates during installation, or configure preferences that the installer labels as optional.

If an optional download fails, record the message and continue only if the installer permits it. The operating system may still install successfully; updates and additional packages can be handled after first boot.

4. Finish and restart

When the installer reports completion, choose its finish, close, or restart option. A reboot means restarting the computer. Ubuntu may ask you to remove the installation media and press a key. Remove the USB device or disconnect the installation image from the virtual machine only when prompted, then allow the restart to continue.

First boot into Ubuntu

First boot means the first startup of Ubuntu after it has been installed. The computer may show a boot menu briefly before displaying a login screen or desktop. Depending on the Ubuntu release and previous selections, an initial setup screen may ask you to choose a region, connect an account, configure privacy, or confirm keyboard and network settings.

Complete only the requested initial configuration. Preferences such as online accounts and privacy choices can usually be reviewed later.
Sign in with the local user account created during installation.
Wait for the desktop to finish loading before judging performance; the first startup can perform additional setup.
Open a basic application and close it again to confirm that the desktop is responsive.

Verify that the installed system is usable

A successful first startup should show Ubuntu’s normal login or desktop environment, not the “Try Ubuntu” session or the installer window from the installation media. Confirm the following:

The computer reaches the installed Ubuntu login screen or desktop without requiring the installation media.
Your account accepts the password created during installation.
The display has the expected resolution and the keyboard and pointing device respond.
The intended storage device is available and the system does not show an installation error.
Network connectivity works if you configured a network connection. A browser or network settings screen can provide a simple check.
You can open the system’s shutdown or restart controls. Use them rather than forcing power off.

After these checks, continue with your course’s first-run, account, desktop, and software-update lessons. If you need a command-focused introduction later, see Essential Linux Commands or Apt Get Command.

Common completion outcomes

Observed outcome | Likely meaning | Recommended next action

Ubuntu login screen or desktop appears after removing the media | Installation completed and the computer booted from the installed system. | Sign in and perform the first-boot checks.

The installer asks to remove the media and restart | The installation is complete and the installer is waiting for a clean transition to the installed disk. | Remove the USB device or disconnect the virtual installation image, then choose restart or press the requested key.

The computer returns to the installer | Installation media is still attached, or the boot order selected the media before the installed disk. | Remove or disconnect the media and restart. If it still happens, inspect the firmware boot-device order.

An explicit installer error appears | A file, storage, network, hardware, or configuration step did not complete. | Record the exact message, identify the last completed step, and investigate before repeating any storage action.

The computer restarts but Ubuntu does not start | The firmware may be selecting the wrong disk or boot mode, or installation may not have completed correctly. | Confirm the intended disk is a boot device, then determine whether the problem is firmware configuration, incomplete installation, or an earlier disk-selection error.

Ubuntu starts but an optional download failed | The core installation may be complete even though an optional package or update was unavailable. | Verify that you can sign in, connect to the network, and perform updates later if needed.

Troubleshooting an interrupted completion

The computer boots back into the installer

Power down or restart using the installer’s available controls if possible.
Remove the USB installation media, or disconnect the ISO from the virtual machine.
Start the computer again and check whether Ubuntu now loads.
If it does not, open the computer’s firmware boot menu or boot settings and place the disk containing Ubuntu ahead of the installation media.
If the intended disk is absent or no Ubuntu boot entry exists, do not immediately repeat the installation. Check whether the installer actually completed and whether the correct disk was selected.

The installer does not finish or restart

First look for an error dialog, a prompt waiting for input, or a message naming the failed step. Note the last completed action. If the computer is still responsive, wait briefly and use the installer’s normal cancel or close path. If it is completely unresponsive, a forced restart may be necessary, but it can leave the installation incomplete.

After an unexpected interruption, return to the installer only after checking the current disk state. Avoid repeating destructive storage steps simply because the installer starts again. Recheck the destination and existing partitions before approving any changes.

Ubuntu does not start after installation

Separate the possible causes:

Firmware selection: The computer may be trying to boot another disk or the installation media.
Installation completion: The final file-copying or boot-configuration stage may have been interrupted.
Earlier storage choice: Ubuntu may have been installed to a different disk than the one selected as the boot device.

Use the firmware boot menu to test the intended disk. If the disk is not listed, inspect hardware connections or virtual-machine disk settings. If it is listed but Ubuntu still fails, revisit the installer’s completion status and the earlier disk and partition choices before attempting repair or reinstallation.

Completion checklist

The installer displayed a successful completion message.
The computer was restarted through the installer’s normal finish action.
Installation media was removed or disconnected at the correct time.
Ubuntu started from the intended internal or virtual disk.
You could sign in with the created account.
The display, input devices, storage, network, and shutdown controls passed basic checks.

When every item is complete, this third installation stage is finished: Ubuntu is installed and usable, and you are ready for first-run configuration and post-installation maintenance.