For my inaugural post in the Being Civil blog, I thought I'd return to my roots and write about the fundamentals. The following post is current, but would have been just as relevant 10 years ago.
First, a Confession…
When I was doing technical support at an Autodesk reseller, I rarely reached out to Autodesk for support. I got frustrated when a frequent answer I received from support was, “Have you tried a full uninstall and reinstall?” I went so far as to lie in my case submissions to describe the error I was getting and end with a snarky, “…and yes, I already tried a clean uninstall!”
Why did I lie? Because I wanted the “magic quick-fix” that I’m sure someone at Autodesk was withholding from me. The reality is that, with rare exceptions, Autodesk support people have the same set of troubleshooting tools available to the public.
What Is a Clean Uninstall?
Most people are familiar with a traditional uninstall. You find the product in the Programs and Features area of Windows and click Uninstall. After a bit of chugging, the icons are gone from the desktop and the product no longer appears in the installed programs listing.
Clean, right? No.
Windows-based products rarely remove all traces of themselves. There are several reasons products leave components behind. Mainly, it is to retain any user-specific settings. When a user re-installs the product, their personal tweaks will still be there. Another reason programs leave stuff behind is to avoid accidentally disrupting other products.
In the case of Autodesk products, you’ll find data left behind in multiple places (more on this later).
Why do a clean uninstall?
I did an experiment on a fresh Windows 7 machine. When Civil 3D 2018 installs with as few options turned on as possible, it installs 32,410 files, 2,738 folders and creates 56, 923 registry keys. Many of those pieces of the installation are also used by other Windows programs (for example, C++ runtime libraries and .NET framework). Windows updates or changes made by other products can change a file version or overwrite a setting.
Most of the time, software can handle minor changes. However, it is difficult to predict when a change to one of the thousands of registry keys or files will result in bad behavior in an Autodesk product. It is also difficult to trace which files or keys is the culprit when things do go wrong. For these reasons, you may be asked by someone at Autodesk support to do a “clean uninstall” and reinstall of a product.
When is it appropriate to do a clean uninstall?
Before you jump head-first into a clean uninstall, take a moment to make sure this is the right option. Some problems cannot be solved by a clean uninstall and reinstall. For example, if your problem is graphic in nature (flickering, blurry, tiny text etc.), it is unlikely that a re-install will help. If the problem seems to be specific to a file and other people are having the same problem, a reinstall is probably not the answer.
Before committing to a re-install, be sure you have checked the usual suspects.
Some scenarios where a clean uninstall may be warranted include:
- errors regarding missing DLL files
- unhandled access violation crashes that cannot be solved by other means
- crashing or unexpected behavior after a Windows update or other product installation
Performing a Clean Uninstall, for Realsies
A clean uninstall refers to using the regular uninstaller plus performing steps to ensure any bad files or registry entries are removed. The following example shows Civil 3D 2017. However, the steps are very similar for all Autodesk products running in Windows. Search “clean uninstall” on the Autodesk website for more details pertaining to other products and platforms.
1. Back up any customizations. In an AutoCAD-based product those files might be:
- User Interface; CUIx
- Local templates; DWT
- Profile; ARG
- Command shortcuts; PGP
- Custom printing/plotting files; PC3, CTB and STB
2. Run the normal uninstalls from the Windows control panel Programs and Features area.
- Be sure to uninstall add-ons and third-party utilities
- Uninstall any lingering material libraries, language packs and object enablers
This can end up being many items if you have multiple languages or add-ons. Uninstall all the items relating to the product you are trying to “clean” off the machine.

3. The most important step separating a clean uninstall from a simple uninstall: Delete the folders:
- C:\Users\[your login]\AppData\Roaming\Autodesk\C3D 2017
- C:\Users\[your login]\Appdata\Local\Autodesk\C3D 2017
- C:\Program Files\Autodesk\Autodesk AutoCAD Civil 3D 2017
- C:\ProgramData\Autodesk\Civil 3D 2017
- C:\Program Files (x86)\Autodesk AutoCAD Civil 3D 2017
These paths will vary per product.
4. Go to REGEDIT.exe
Verify that the following keys were removed (they should be gone, but double-check):
- HKEY_CURRENT_USER\Software\Autodesk\AutoCAD\R21.0\ACAD-0000:409\
- HKEY_LOCAL_MACHINE\SOFTWARE\Autodesk\AutoCAD\R21.0\ACAD-0000:409\
The exact registry values will vary per product. Check out JTB World's all-in-one list to find your products' numbers.
5. Clear the contents of the %temp% directory. (details)
6. Reinstall your product
- Temporarily disable your antivirus program.
- Temporarily disable Windows UAC
Your IT department may push back on this. However, if you continue to have problems with a product, the antivirus may be blocking certain features from installing.
- You must be logged in as administrator to install Autodesk products and updates
The clean uninstall process can be tedious, but it will be faster to start with a clean slate than to hunt down which files or registry keys have gone haywire.
The Future
One of the many upsides of cloud-based software is the lack of installed components. Cloud-heavy products, like Fusion 360 and InfraWorks have a smaller installed footprint since many of the calculations occur in the cloud. Autodesk's BIM 360 suite of products and AutoCAD 360 are delivered to you as a service through a web browser. The era has arrived where troubleshooting software starts with a browser refresh.