I’m new with Arc 10, and I'm struggling alot. When using Geoprocessing I’m getting the same error or message again and again. "ERROR 999998: Unexpected Error"

I have checked all the settings I can think off. Any help or recommendation will be greatly appreciated.

  • 11
    Welcome to GIS SE. Can you provide us a little more detail in your question (e.g. what tool you are using, data type, service pack installed...etc)?
    – artwork21
    Jun 11 '12 at 12:10
  • lol. Thats a good comment. May be the toolbox you are using and you gave a file name for export. Did you assign extension to that file? Your export file name should have desired extension else you get errors.
    – Naresh
    Jun 11 '12 at 15:14
  • The answer given by James England above works really well. I was trying to execute a variety of processes on ArcGIS 10.0, and no matter what I did, I too kept getting the "ERROR 999998: Unexpected Error" on every process. I even got this error when I tried to create a raster dataset (Data Management Tools > Raster > Raster Dataset > Create Raster Dataset) -- seriously, like the simplest thing to do on ArcGIS. However, once I unchecked the box next to "Enable" under the "Background Processing" section of the "Geoprocessing Options" menu, everything started working again.
    – user20814
    Aug 6 '13 at 23:45

Change the processing to foreground instead o background. You can control whether tools execute in the foreground or background by clicking Geoprocessing > Geoprocessing Options on the Standard toolbar.

The Background processing panel is where you control whether a tool executes in foreground or background mode.

If Enable is checked, tools execute in the background, and you can continue working with ArcMap (or other ArcGIS applications, such as ArcGlobe) while the tool executes. You'll see a progress bar at the bottom of your document displaying the name of the currently executing tool. When the tool finishes executing, a pop-up notification appears on the system tray. You can control how long the notification message appears by moving the Notification slider or disable the message by moving to the far left.
If Enable is not checked, tools execute in the foreground. When a tool is executing in foreground mode, you must wait until the tools stop executing before you can continue with other work.
  • 1
    Theres no information in the original post or comments to indicate they're using background processing nor an explanation on how this would help.
    – KHibma
    Oct 16 '12 at 16:13
  • that's a good solution for this error :)
    – geogeek
    Feb 15 '13 at 8:44
  • @geogeek it worked for me as well :)
    – Shiko
    Oct 25 '16 at 14:51
  • Worked for me thanks. Though i am still looking into this as to why this happened and why this solution proved to be a resolution Feb 10 '19 at 9:49

I copy/pasted "ERROR 999998: Unexpected Error" into the search box of support.esri.com and found an Online Help entry describing it:

999998 : Unexpected Error.


This is an operating system error and can indicate different error conditions. These errors are not specifically documented in the ArcGIS Desktop Help system. However, in most cases, the error description provided with the error code can be used to look up additional information on the operating system.


If the error message is "Unexpected Error," consider contacting technical support for assistance. If the message attached to the 999998 error is any other message, these messages are standard operating system errors that can be looked up under Websites such as Microsoft's Support and Help Website (http://support.microsoft.com/search/?adv=1) for more information.

Whether you contact your local technical support, or seek assistance from a forum like this, my recommendation is to provide the details that @artwork21 suggests (i.e. what tool you are using, data type, service pack installed, etc) at the outset, so that anyone trying to help has a better chance of understanding and reproducing what you are experiencing.


I was using the map algebra calculator and received this same error message. I tried these tricks to no avail:

  • Cleared memory
  • Removed "%" out of a layer name

This is how I got it to run:

  • I saved it to my desktop

I found that by increasing highlighted value 65536 to max bellow calculation and many others for raster cannot be achieve

Con(IsNull("raster"), FocalStatistics("raster", NbrRectangle(5,5, "CELL"), "MEAN"), "raster")

With max value 50000000 – still working and all above - no

  • You should be more precise in your answer : where is this value of 65536 you refer too ? NB : I removed your personal info from your answer (you might get unwanted calls and spam). Seems somebody didn't understand your answer and downgraded it.
    – gisnside
    Jan 29 '18 at 8:20

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