System Requirements & Prerequisites

Petroleum Office is an Excel add-in built on the .NET 10 Desktop Runtime. The installer checks for the runtime up front and refuses to install if it is missing. If you hit a runtime error, install the matching runtime first, then re-run the Petroleum Office installer.

Most modern Windows machines already have what they need. Recent Windows 11 installs with current Microsoft 365 Apps usually have the runtime preinstalled or auto-updated by Windows Update. Older machines, fresh Windows installs that have never run Office, and Windows 10 LTSC or Windows Server installs typically do not have the runtime preinstalled — you will need to add it before Petroleum Office can load.

Supported environments

  • Operating system — Windows 10 (1809 or newer) or Windows 11. Windows 7 and Windows 8 are not supported because .NET 10 itself does not run on them.
  • Microsoft Excel — Excel 2016, 2019, 2021, or Microsoft 365 for Windows. Both 32-bit and 64-bit Excel are supported.
  • .NET 10 Desktop Runtime — required, in the bitness that matches your Excel (see Step 1 below).

Excel for Mac and Excel on the web are not supported.

Step 1 — Find out which Excel you have (32-bit or 64-bit)

  1. Open Excel.
  2. Click File in the top-left corner.
  3. Click Account at the bottom of the left sidebar. On older Excel versions click Help instead.
  4. Click About Excel.
  5. The dialog header shows the version and the bitness, for example:
    • Microsoft® Excel® for Microsoft 365 MSO (Version 2401 Build 17231.20000) 64-bit
    • Microsoft® Excel® 2019 MSO (16.0.10396.20023) 32-bit

The bitness is what matters for choosing the right runtime. The Excel year (2016 / 2019 / 2021 / 365) does not.

Step 2 — Install the .NET 10 Desktop Runtime that matches your Excel

Download from Microsoft's official page: dotnet.microsoft.com/download/dotnet/10.0

On that page, scroll to the .NET Desktop Runtime 10.0.x section. Two downloads matter:

Your Excel Download this File name looks like
64-bit Excel .NET Desktop Runtime — Windows x64 windowsdesktop-runtime-10.0.x-win-x64.exe
32-bit Excel .NET Desktop Runtime — Windows x86 windowsdesktop-runtime-10.0.x-win-x86.exe

Do not download the SDK, the ASP.NET Core Runtime, or the plain Runtime — only the Desktop Runtime works. The add-in needs WPF, which only ships in the Desktop Runtime.

You can install both x64 and x86 side by side without conflict. This is useful on shared machines, or if you might switch Excel bitness later.

Run the installer (about 50 MB) and accept the defaults. No reboot needed.

Step 3 — Install Petroleum Office

Re-run the Petroleum Office installer. The preflight check will pass and the add-in will load the next time you start Excel.

Troubleshooting

Excel says "It was not possible to find a compatible framework version". The .NET 10 Desktop Runtime is missing, or the bitness does not match your Excel. Follow Step 1 to confirm your Excel bitness, then Step 2 to install the matching runtime.

You installed the x64 runtime but Excel still will not load the add-in. You probably have 32-bit Excel. Install the x86 runtime in addition — they do not conflict.

The installer says "Petroleum Office requires the .NET 10 Desktop Runtime" even though you just installed it. Make sure you installed the Desktop Runtime, not the plain Runtime (without "Desktop") or the ASP.NET Core Runtime. Open the installer page again at dotnet.microsoft.com/download/dotnet/10.0 and pick the row labelled ".NET Desktop Runtime".

The installer asks for both x86 and x64 runtimes. This happens when the installer can't pin your Excel's bitness from the registry — typical for Office editions that don't include Outlook (Office Home & Student, standalone Excel) or unusual side-by-side installs. The safest fix is to install both runtimes (they don't conflict, ~50 MB each). Alternatively, confirm your Excel bitness from Step 1 and install only the matching one.

You are on Windows 7 or Windows 8. .NET 10 does not support these. Upgrade to Windows 10 1809 or newer, or use Windows 11.

You installed the right runtime but the add-in tab still does not appear in Excel. See Troubleshooting Common Errors in Petroleum Office and Getting Started with Petroleum Office for the next set of checks.

If you have followed these steps and the add-in still will not load, contact support — include your Excel version (the full "About Excel" string), the Windows version, and whether the installer succeeded or failed.