This became such a huge issue for me that I was getting so nervous, stressed, and sweaty when getting assigned a task to reinstall the Office suite for a user. This problem was repeating itself for at least 30% of installations and I was seriously despising Microsoft for creating such a buggy installer. No matter how I tried, SaRa tool, Office Deployment Tool, the usual Office.com installer some machines just refused to install and always got stuck at 2%, 51%, 58%

It is a huge chance it’s the firewall – At least it was for me.

After months of loathing, testing different scenarios, plain guessing, checking those gibberish installation logs, I noticed that when asked the user to connect to different network source – Wi-Fi or direct cable the problem seemed to solve.

I started messaging Networking guys, stating that there is some weird problem with the network. Something is blocking Office suite and it is getting stuck. They assured me that nothing is wrong, office endpoints are definitely not blocked.

At this point I was so tired of this issue, I started to instruct the user to switch to any other network that is not connected to company.

One day, accidentally I ran into this thread on Reddit with similar issue. One user noticed that when specifically whitelisting all known endpoints in the firewall the issue was gone. Then it clicked for me. I have immediately sent an e-mail to the networking guys with KB’s and how-tos, begging them to implement.

Apparently, in our case, Sophos Firewall was inspecting Microsoft packets for too long and the office installer was timing out all the time. By whitelisting them in Sophos Exclusions the problem was gone!

You can use this list for any firewall you use in your environment.
https://support.sophos.com/support/s/article/KB-000038173

Traditional step-by-step instructions

1)  Try using SaRa Tool to install office

Go to SaRa Tool, click “Download”, save and execute the file.

You will be prompt with a window, click “Install”

In the menu, “Which app are you having problems with?”, select “Office”, click “Next”.  Choose first option, “I have an Office subscription, but I’m having trouble installing it” and click “Next”, follow further instructions.

2) Try Office Deployment Tool

Even though it is a bit advanced technique, this method worked for me far better than SaRa tool.

Go here: Microsoft Office Deployment Tool and download the executable. Install all the contents into specific folder under: “C:\Office_Installer”. (create the folder first). You will be left with “setup.exe” and 3 configuration files.

You can use these to check up examples or I would suggest to use a special tool to create these type of files at config.office.com or Deployment Tool Examples or you can use my config, most of the time it should fit for you. It is just a basic Office without anything else for users who has “Bussiness Standard/Premium” licenses.

So, go to yours “Office_Installer” folder, create a new file called “Configuration.xml” and paste this content:

<Configuration>
  <Add OfficeClientEdition="64" Channel="Monthly" SourcePath="C:\Office_Installer" AllowCdnFallback="TRUE">
    <Product ID="O365BusinessRetail">
      <Language ID="en-us" />
      <ExcludeApp ID="Groove" />
    </Product>
  </Add>
  <Property Name="SharedComputerLicensing" Value="0" />
  <Property Name="PinIconsToTaskbar" Value="TRUE" />
  <Property Name="SCLCacheOverride" Value="0" />
  <Property Name="AUTOACTIVATE" Value="0" />
  <Property Name="FORCEAPPSHUTDOWN" Value="TRUE" />
  <Property Name="DeviceBasedLicensing" Value="0" />
  <Updates Enabled="TRUE" />
  <RemoveMSI>
    <IgnoreProduct ID="InfoPath" />
    <IgnoreProduct ID="InfoPathR" />
    <IgnoreProduct ID="PrjPro" />
    <IgnoreProduct ID="PrjStd" />
    <IgnoreProduct ID="SharePointDesigner" />
    <IgnoreProduct ID="VisPro" />
    <IgnoreProduct ID="VisStd" />
  </RemoveMSI>
  <AppSettings>
    <User Key="software\microsoft\office\16.0\excel\options" Name="defaultformat" Value="51" Type="REG_DWORD" App="excel16" Id="L_SaveExcelfilesas" />
    <User Key="software\microsoft\office\16.0\powerpoint\options" Name="defaultformat" Value="27" Type="REG_DWORD" App="ppt16" Id="L_SavePowerPointfilesas" />
    <User Key="software\microsoft\office\16.0\word\options" Name="defaultformat" Value="" Type="REG_SZ" App="word16" Id="L_SaveWordfilesas" />
  </AppSettings>
  <Display Level="None" AcceptEULA="TRUE" />
  <Logging Level="Standard" Path="C:\" />
</Configuration>

Our plan is to download Office FIRST and then INSTALL it second. So, open your “command prompt”, and type:

cd C:\Office_Installer, press Enter, then type:

setup.exe /download Configuration.xml

This will download all the Office Content in our created directory at “C:\Office_Installer”. It can take a while, depending on your internet speed. If it fails to download, you will have to do it on a different computer. (That is probably the reason why you couldn’t install it in the first place). After successfully downloading the Office files you should have a look like this:

(notice the new “Office” directory)

Thirdly, paste this in the “command prompt”, this will install the office suite by using the files in “Office” directory.

setup.exe /configure Configuration.xml

Good luck,

Audrius.