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Windows: How to Download, Install, and Start APT

Supported Systems

APT is supported on Windows 8.1 (and higher). Please note that APT may or may not work on operating systems that are past their "end-of-life" (and it may be difficult to trouble shoot unfamiliar issues).

APT is only available as a 64-bit version for Windows. (To determine which you have look at the System information in the Control Panel.)

Depending on your institution's computer security measures (firewalls, blocked ports, etc.), you may initially have communication trouble with APT. If you have any concerns please see our Server Connectivity knowledge article.


1. Uninstall the previous version

If you are going to install APT in the same folder as a previous version, please remove the previous version first. If you are going to install in a separate folder, you still might consider uninstalling to save disk space (and possible confusion between the different versions).

Here are instructions for getting rid of the old APT:

  • Delete the APT installation folder.
  • Remove the link to the deleted installation that is in your Start Menu (in the STScI folder) by right clicking and deleting.


2. Download and install

Download the installer below and double-click install-windows-apt.exe to start the installer.

Install APT to a folder you have default privileges for: We recommend installing this software into the default location (which is a folder within the user's home folder). In situations where APT must be installed into a common area (such as C:\Program Files), you may need to use an actual Administrator account and not an account that has Administrator privileges or some institution-specific configuration of heightened privileges. If you choose to install to this location, please be sure to specify a folder within Program Files e.g. C:\Program Files\APT_202x.x.

(If you have trouble installing APT, please see the Troubleshooting Tips at the bottom of these platform specific Installation instructions.)

Download the Installer

View the SHA Number


3. Start

Once you have installed APT, you can invoke it from the Start menu if you have created shortcuts. For instance if you chose the default shortcuts, go to Start menu and choose Programs>STScI>APT_202x.x>APT. If you did not create shortcuts, you may invoke APT from the APT installation folder.


4. How to find out about new releases

We maintain a distribution list for announcing new releases of APT. This may be helpful to people who install APT for others to use. Just send a blank email to: (Unsubscribe by sending a blank email to


5. Troubleshooting

If there are problems with the installation you can turn on debug logging and sometimes that will reveal the problem. This debug log would also be useful to send us if you can't figure out the problem. Contact us (through if you have problems with installation.

To turn debug logging on during installation:

  • bring up the command prompt (Start>Accessories>Command Prompt)
  • cd to the folder where the install-windows-apt.jar file was created. (This file is probably where you saved the installer - i.e. your Downloads folder. Note that you cannot turn debug logging on until the install-windows-apt.exe file has been opened, which then creates the install-windows-apt.jar file.)
  • type: jre10\bin\java -DTRACE=true -jar install-windows-apt.jar

To turn debug logging on while running APT: Go to the APT installation folder and double click on the APT.bat icon.

Known Installation/Download Problems:

  • We have recently had two instances of people having problems installing APT on Windows due to heightened security in their anti virus software. Contact us (through if you have problems with installation. (92940, 92850)
  • "Windows protected your PC"
    This message appears because the Microsoft Defender SmartScreen does not recognize the APT application. Click "More Info" then "Run anyway". (93073)