STEP 7 V5.5 won't install on Windows 11 — how to run it

STEP 7 V5.x (SIMATIC Manager) is the programming software for S7-300 / S7-400 — still used on many machines in Vietnam. But it was built for Windows XP/7, so on Windows 10/11 it often throws install errors, license errors, or can't connect to the PLC. This is an OS-compatibility issue, not a faulty PLC.

Common issues

1. Won't install — compatibility error, or the Automation License Manager won't run.
2. Lost license — the license “vanishes” when cloning/ghosting the drive or swapping PCs.
3. Can't see the PLC — the PC-Adapter USB/MPI or CP driver won't run on new Windows.
4. Font/display issues — high DPI breaks the SIMATIC Manager UI.

How to handle it

1. Use a Windows 7 VM Create a VM (VMware/VirtualBox/Hyper-V) with Windows 7 + STEP 7 V5.5 — the most stable environment, isolated from the host.
2. Install in the right order Install the Automation License Manager first, then STEP 7; run the installer as Administrator + Compatibility (Windows 7).
3. Handle the license Transfer it via the Automation License Manager (don't copy by hand); keep the original, don't ghost the drive and break the key.
4. Connect the PLC In the VM, pass through the USB PC-Adapter; pick the right PG/PC Interface (MPI/PROFIBUS/TCP). Old CPs need their matching driver.
5. Fix DPI/scale Set scale to 100% or enable “override high DPI” for s7tgtopx.exe to stop the UI breaking.
6. Back up the whole VM Save the VM file as your “toolkit” — next time it just runs, no reinstall.

When to call an expert

If the license keeps “vanishing”, the cable driver won't load, or you need a proper “toolkit” VM for long-term S7-300/400 work, DeepDebug can build it and support upload/edit remotely — even for distant machines.