This post fromMiniTool Solutionwill help you.

It will offer you 3 useful methods to fix it.

Another installation is in progress.

Clean Boot VS. Safe Mode: What’s the Difference and When to Use

You must complete that installation before continuing this one.

Another cause of this error is the corrupted registry file.

Even if you restart the computer many times, you will still get the same error.

go to Services and select Open Task Manager

How to Fix Another Installation Is in Progress?

Firstly, you should fix the corrupted registry files.

On the other hand, it’s possible for you to fix registry files with Advance System Repair Tool.

disable Windows Installer

There are thousands of small system files working there for specific tasks.

Here is a quick guide on how to fix this error with Advance System Repair Tool.

Step 1: Clickhereto download Advanced System Repair Tool and install it.

Top 4 Ways to Windows Installer Service Could Not Be Accessed

Step 2: Open this tool and use it to scan your Windows PC.

Step 3: After scanning, click theFIX ALL NOWbutton to repair error.

This mode enables your PC to start without loading any third-party software and driver.

In this way, you might prevent conflicting problems while installing software.

Here are the steps to starting PC in Clean Boot mode.

Safe Mode: whats the difference, when and how to use?

Step 1: Press theWinkey +Rkey to open theRunbox.

Next, typemsconfigand clickOK.

Step 2: TheSystem Configurationwindow will show up.

Go to theServicestab, checkHide all Microsoft servicesand then clickDisable all.

Step 4: ClickApplyandOK.

Then, you’re able to kickstart your machine in Clean Boot state.

Editing registry file could be risky, so you better do it safely following the steps below.

Step 1: Press theWinkey +Rkey to open theRunbox.

Next, typeregeditand clickOK.

When theUser Account Controlwindow pops up, clickYes.

Step 2: Now, go to this path:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Installer\InProgress.

If you cant find this key, navigate to:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer.

Step 3: Locate theDefaultvalue on the right.

If you find data inside it, double-click it and clean it.

Step 4: Open theRunbox again.

Next, typeservices.mscand clickOK.

Step 5: FindWindows Installer.

Double-click it and setStartup typetoDisabled.

Step 6: reboot your system.

Step 7: FindWindows Installeragain.

Now, have a go at drop in the system again.

The problem should be removed.

Troubled by the issue Windows Installer service could not be accessed?

Here, try these 4 ways to fix Windows Installer error.