Note: This patch requires that Keysight IO Libraries version 15.0 is already installed. Download Keysight IO Libraries Suite 15.0 Patch 1

What Does this Patch Correct?


IO Libraries Suite 15.0 has a defect where new I/O sessions, or utilities in the Keysight IO Libraries Suite, will fail to open after a PC has been continuously running, without reboot, for greater than 24 days. I/O sessions that were opened in the first 24 days will continue to run as expected, even after the 24 day mark.

The root cause of this problem is a .NET Framework call that does not operate as defined in the Microsoft documentation. Rebooting the PC, or restarting the KeysightIOLibraries service from the Windows Services applet, will reset this “24 day clock”.

Problem Symptoms:


  • The Keysight Connection Expert will not open. When you attempt to open it, the following dialog is displayed even though another copy of the Keysight Connection Expert is not running:













  • If Keysight Connection Expert is running when the problem occurs, a refresh will show both interfaces and instruments in a failed state.
  • Interactive IO will start but you cannot successfully connect to an instrument. If a copy of Interactive IO is already running and connected to an instrument when the problem occurs, it will continue to function normally and will be able to communicate with the instrument.
  • Visa Assistant will hang indefinitely displaying the following dialog:












  • The only way it can be shutdown is to kill it (va.exe) with the Windows Task Manager. Note that leaving Visa Assistant running in this case causes a memory leak which will eventually (overnight in my case) to run low on virtual memory. If Visa Assistant is running before the problem starts, it will continue to run and you will be able to communicate with the instruments it displays.
  • ViFind32 will display the following Application Error dialog:


App Err








  • and it will terminate when the dialog box is dismissed.

Uninstalling the Patch


Windows Control Panel ("Add or Remove Programs" in Windows XP or "Programs and Features" in Windows Vista) lists both "Keysight IO Libraries Suite 15.0" and "Keysight IO Libraries Suite 15.0 Patch 1".

  • If you remove only Keysight IO Libraries Suite 15.0 Patch 1, then Keysight IO Libraries Suite 15.0 will be reinstated to its original state.
  • If you remove only Keysight IO Libraries Suite 15.0, but not the Patch 1, then IO Libraries will not run. You must uninstall the Patch1 and then reinstall Keysight IO Libraries Suite 15.0.
  • Future editions of Keysight IO Libraries will install over both Keysight IO Libraries Suite 15 AND the Patch 1. Both will be removed from the Windows Control Panel.
  • Use Windows Control Panel ("Add or Remove Programs" in Windows XP or "Programs and Features" in Windows Vista) to remove the programs. Do not delete files directly.

Removing the IO Libraries Suite does not delete the standard VISA directory, standard VISA COM files, standard IVI (Interchangeable Virtual Instrument Foundation) files, and IVI Shared Components. There is no reliable way for the IO Libraries Suite uninstaller to be sure that no other installed product (whether from Keysight or another vendor) is using these files and directories.