Topic: Windows

Here are the step-by-step installation notes for Windows users. They are also available, (with pictures!) in the VEW Handbook, available from in the support section.

(A) Installing a Java Development Kit (JDK)
(see note below about 64-bit)

1. Download and run the latest JDK installer from - Choose the simplest "JDK Update"
2. It comes with a public JRE, which you should also let it install. (I set the install directory to jre1.8.0_91)
3. By default, the installation will be to a directory similar to C:\Program Files\Java\jdk1.8.0_91
4. Go into Settings, Control Panel, System, Advanced, Environment Variables.
5. Ensure that "C:\Program Files\Java\jdk1.8.0_91\bin" is in the PATH variable.
6. Also remove any references to any older versions of the JDK you may find on the PATH.

(B) Upgrading the JDK

The most reliable way of ensuring you are running the latest version is to uninstall any other versions from Control Panel, Add/Remove programs, so that the latest version is the only version you have installed. Then go through the steps in (A). I know it's a bit tedious, but it does keep everything clean and tidy. Ideally, you should copy the new version of tools.jar into VEW's directory and recompile, but in general unless you are jumping from Java 8 to Java 9, it won't be strictly necessary.

(C) Installing the VEW


To compile/update/even run the VEW, you need to be able to create files - ie, you must be an administrator. Windows Vista by default makes it extremely tedious to run the VEW as administrator; it wouldn't let us tick the "always run as admin" box, so we had to explicitly choose Run As Admin every time. The only way I found to make this sane was to turn off UAC - go to Control Panel, User Accounts, and for the desired account, click on "Turn User Account Control on or off", then choose to turn it off. I know this probably isn't the most secure thing, (although we seemed to be ok in older OSes without all these tiring confirmation windows every time you click anything), but I tried all other possible options involving keeping UAC on, and none of them allowed me to get past step 4, without it complaining about writing files, and eventually failing. Thanks Vista...

1. Obtain the windows installer by contacting us.
2. Run the installer.
3. Copy C:\Program Files\Java\Jdk1.8.0_91\lib\tools.jar into C:\Program Files\VEW\VEW - assuming the installer used the default installation directory. When pasting, you should be in the same directory as "vew.bat".
4. Choose Start, Programs, VEW, Compile VEW from the Windows start menu. You will only need to do this once.
5. Choose Start, Programs, VEW, Run VEW.
6. If a red "Update" button is visible, click it, to download and patch the VEW to the latest version.
7. ALSO, you may like to populate the C:\Program Files\VEW\ScenarioData directory with the input climate data. If the VEW cannot find the data, it will ask you to locate it when it needs it.


VEW runs fine in 32-bit or 64-bit modes. It will use whatever Java installation you have - essentially, whatever version of Java runs when you type "java" at a command line, will be used to run the VEW, and it doesn't mind which. If you run models that require more than 4Gb of RAM though, then 64-bit is the way.