We have a copy of ArcGIS 10 that we are preparing to use to upgrade our existing ArcGIS 9.3 installation.

Should I uninstall ArcGIS 9.3 first?

Or do I install ArcGIS 10 over it?

Are there any best practises or guidelines I should be aware of?

2 Answers 2


You must uninstall a previous version of ArcGIS software before installing a new one. In fact, the install programs will require it. In addition, I suggest that if you have any Esri or 3rd party tools that you uninstall them first, before uninstalling ArcGIS 9.3.

A related question was asked earlier, How do I cleanly uninstall ArcGIS 9.3.1 extensions after ArcGIS 9.3.1 is uninstalled?

ArcGIS 10's default installation location is different from 9.3.1, so that helps minimize some possible conflicts. Here are the steps that I would follow:

  1. Uninstall any tools.
  2. Uninstall any SDK or ArcGIS extensions.
  3. If you have ArcInfo workstation intalled, and plan to install ArcInfo workstation 10, uninstall it.
  4. Uninstall ArcGIS Desktop.

You also might want to look through the ArcGIS installation forum.

Std Disclaimer: I am an Esri employee, but not on the install team.

  • @MkKennedy: I don't know why ESRi does not provide the automatic uninstallation/upgrade of ESRI products functionality in the installer itself...just like MS Office. Can you please ask the installation team guys and let us know...I mean is there a technical reason or just it was never thought of and going like that for years!
    – ujjwalesri
    Jun 17, 2011 at 5:20
  • 2
    @ujj ESRI provides Web pages for users to request enhancements and bug fixes. ESRI employees replying on this site usually do so as individuals, not representatives of ESRI, so it is unfair to ask them to circumvent established channels to forward requests.
    – whuber
    Jun 17, 2011 at 14:17
  • 1
    @ujjwalesri: Bill (whuber) is right; it's better to ask through established channels. Someone might have requested it already. There are a few requests at ideas.arcgis.com/ideaView?id=087300000008IO3AAM (search 'install'). At this moment, I think the install team is pretty busy trying to finish beta 1 tasks! They did add the ability to uninstall service packs recently, which is a big improvement. If only hot fixes/patches could be uninstalled...
    – mkennedy
    Jun 17, 2011 at 20:04

Best practice is to generally remove older versions of software before installing new ones unless there is a chance of interfering with complicated custom settings, although these may be overwritten anyways.

That being said, you can install Arc10 over an existing 9.3 version and it will work.

  • 8
    When it comes to ArcGIS software (and Esri software in general), you have to uninstall previous versions. In fact the installer will not work and tell you it's because there's a previous version installed.
    – mkennedy
    Jun 16, 2011 at 18:44

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