Known bugs, issues and workarounds

In the following a list of known bugs and issues in specific setup versions of itom are listed. Some of these bugs can be overcome by the listed workarounds or solutions:


Error message from Python packages
If some Python packages (matplotlib, scipy, numpy) return an error message that a dll-file can not be loaded, the Visual C++ Redistributable is not correctly installed. Try to reinstall it. The current version can be downloaded here:
Error message regarding PYTHONHOME variable
If a new itom setup version is installed on a computer with an already installed itom and Python can not be started, it may be a problem with python environment variables. First, delete this variable, reboot your system und install itom again.

itom 3.0.0

Error message at startup: python35.dll could not be found (fixed in version 3.0.0)
From Python 3.5 on, the Windows installer does not copy the corresponding DLL libraries to the Windows system directory. Please make sure that the Python directory, containing the requested DLL library is added to the PATH environment variable of Windows. Usually this is automatically done within the Python installer, however it is possible to unselect this option. Re-logon to your Windows session in order to let Windows reload this environment variable. See for information how to add a value to the PATH environment variable in Windows.
Scaling problems on high-resolution displays (4k) (fixed in version 3.0.0)
itom for all versions up to 2.2.1 will not be properly scaled on high-resolution displays. We are currently working on this issue to improve the problem. In order to overcome this problem (Windows only), it is possible to tell Windows that an application is only prepared for 96dpi (default) screens such that Windows will internally handle the scaling for 4k displays. Place the following manifest file (qitom.exe.manifest) into the same folder of itom to start the application in the compatibility mode. For more information see

itom 2.1.0

itom crashes at startup when python should be loaded.

Problem: There are two known reasons for this crash. The first is, that you probably installed python with another user than the one you are currently logged in. When the python library (see above) is loaded at startup of itom, it interally tries to find out, where the entire python installation including the modules and packages are located on your harddrive. Usually, this information is contained in the Windows registry. However, if Python has been installed under a local or different user, the registry information cannot be properly read. In this case, either reinstall Python as adminstrator and for all users or set the environment variable PYTHONHOME (see to the base directory of Python (the directory where the Python executable is located).

Another problem might be, that your computer has a default charset that differs from the european or american one (e.g. russian operating system). In this case, a known bug is contained in the qitom.exe application of the 32bit and 64bit Windows setup. There is a corrected application file for the 64bit setup. Download the archive from and replace the file qitom.exe by the one in the zip-file.

Both issues will be fixed in upcoming itom versions.

itom 1.4.0

Qt Designer does not start
There is a known issue in the former setup 1.4.0 concerning an unsuccessful startup of the external Qt designer. If you want to open the designer using the button in the toolbox of the itom main window, the startup may fail. This bug is known and will be fixed in future releases. Until then, please open the designer either by starting the designer.exe in the application folder of itom or open an existing ui-file (e.g. in the demo folder of itom).