Resolving SINAMICS STARTER Installation Restart Loop on Windows 8

1. Problem Overview

The SINAMICS STARTER commissioning software (used to parameterize SINAMICS S110, S120, G110M, G120, G120C, G120D, G120P, S210, and the SIMOTION/SIMOTRIN-related drive line) occasionally fails to install on Windows 8 and Windows 8.1 64-bit systems. The visible symptom is a permanent restart loop:

1. Engineer launches setup.exe from the STARTER install media or extracted download folder.
2. Windows Installer initializes and immediately displays the dialog "Please reboot before installing any more programs".
3. The engineer restarts the workstation per the prompt.
4. On the next boot, setup.exe is re-launched (manually or via RunOnce) and the identical dialog appears again.
5. The cycle never terminates; STARTER is never installed.

The dialog itself is generated by Windows Installer (the msi engine) when it detects pending file rename or delete operations stored in the registry. The InstallShield and MSI bootstrapper shipped with STARTER V4.3, V4.4, V4.4 HF1, V4.4 HF2, and V4.4 HF3 interpret this state as fatal and refuse to continue, instead demanding another reboot. Because the reboot does not clear the registry entries, the dialog is produced indefinitely.

2. Affected Software and Drive Firmware Combinations

The installer loop is not tied to a specific SINAMICS firmware version. Any drive that pairs with STARTER can be involved, but the affected software envelope is narrow:

Because STARTER is a 32-bit application (it ships as STARTER.exe with WOW64 redirection in %ProgramFiles(x86)%\Siemens\Automation\SIMATIC_STARTER), the 64-bit Windows 8 install path is technically permitted, but the InstallShield bootstrapper's OS check rejects 6.2/6.3 kernel builds before reaching the compatibility shim.

3. Root Cause Analysis

The "Please restart Windows before installing any more programs" message originates from Windows Installer when one of the following keys is non-empty in the registry of the local machine:

RebootRequired

On Windows 8/8.1, three conditions commonly leave PendingFileRenameOperations non-empty even after a clean boot:

1. Incomplete prior MSI transaction. A previous attempt to install STARTER (or another MSI: TIA Portal, STEP 7, WinCC) was terminated mid-transaction. The MSI service committed the file rename queue but did not finalize the package state.
2. Windows Update pending reboot. KB2911101, KB2919355, KB2953522, or the Windows 8.1 Update 1 rollup left RebootRequired=1. STARTER's bootstrapper checks this key and aborts.
3. Antivirus or backup agent file lock. Real-time scanners (Trend Micro, McAfee, Sophos, SEP) hold a handle on a file Windows wants to replace. The rename is queued but cannot complete, so the queue never drains.

The STARTER bootstrapper (setup.exe) uses InstallShield Limited Edition. It calls MsiBeginTransaction and then checks the four registry paths above. If any are dirty, it issues the dialog and writes itself into RunOnce. After reboot, it runs again, finds the keys still dirty (because the underlying condition has not been fixed), and repeats. The engineer therefore observes what appears to be an installer bug, but is actually a Windows Installer safety mechanism protecting against corruption.

4. Pre-Installation Checklist

Before touching the registry, complete the following prerequisites. Skipping these is the most common reason the registry fix appears to fail:

1. Sign in with a local Administrator account. Standard user tokens cannot edit HKLM.
2. Disable UAC virtualization for the install session. Open cmd.exe as Administrator and run set __COMPAT_LAYER=RunAsInvoker only if UAC is silently dropping privileges on legacy installers.
3. Stop and disable third-party antivirus. Real-time file-system filters must be unloaded before MSI operations.
4. Disable Windows Update automatic reboot. Settings → PC settings → Update and recovery → Windows Update → Choose how updates are installed → "Never search for updates (not recommended)". Use wuauclt /detectnow later to check status.
5. Stop the Windows Installer service. net stop msiserver and confirm no msiexec.exe processes are listed in Task Manager.
6. Verify .NET Framework 3.5 and 4.x. STARTER V4.4 requires .NET 3.5 SP1 and .NET 4.0; Windows 8.1 ships with .NET 4.5 but does not enable 3.5 by default. Install via dism /online /enable-feature /featurename:NetFx3 /all /source:D:\sources\sxs.
7. Verify 2 GB free on the system drive. InstallShield unpacks to %TEMP% and the unpacked payload is ~1.4 GB.
8. Confirm the install media integrity. Re-download the DVD ISO from the Siemens Industry Online Support portal and verify the SHA-1 hash against the delivery release list.

5. Solution 1: Clear PendingFileRenameOperations and RebootRequired

This is the documented workaround for the Windows Installer reboot loop. It is identical to the procedure referenced in the original Siemens escalation thread and is valid for Windows XP through Windows 10 for any MSI bootstrapper that produces the same dialog.

1. Press Win + R, type regedit, press Enter. Approve the UAC prompt.
2. Navigate to HKLM\SYSTEM\CurrentControlSet\Control\Session Manager.
3. In the right pane, double-click PendingFileRenameOperations.
4. Select the entire contents (the value is multi-string, e.g. \??\C:\Users\...\file.tmp|\??\C:\Program Files\...\file.dll) and press Delete. Confirm.
5. If the key does not exist, leave it alone; do not create it.
6. Navigate to HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\RebootRequired.
7. If RebootRequired exists with value 1, delete the value (not the key).
8. Navigate to HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer and delete InProgress if present.
9. Close Registry Editor. Do not reboot yet.
10. Open cmd.exe as Administrator and run:
    net stop msiserver & net stop wuauserv & net stop BITS
11. Wait 30 seconds, then run:
    net start msiserver & net start wuauserv & net start BITS
12. Run setup.exe from the STARTER install media with administrative elevation (right-click → "Run as administrator").

If STARTER now installs correctly, the registry was the cause. If the dialog reappears, the registry keys were repopulated by another agent (most commonly an antivirus self-update or Windows Update). Repeat the inspection during the install attempt, just before the dialog appears, to identify the writer.

6. Solution 2: Disable the Installer Reboot Check via Group Policy

For managed environments where registry edits are controlled by Group Policy, the MSI reboot prompt can be neutralized at the policy level. Note that this does not fix the underlying pending state; it only prevents STARTER's bootstrapper from checking it.

1. Open gpedit.msc (Windows 8/8.1 Pro/Enterprise only; not available on Core).
2. Navigate to Computer Configuration → Administrative Templates → Windows Components → Windows Installer.
3. Enable "Turn off Windows Installer during system maintenance" with the radio button "Never".
4. Enable "Always install with elevated privileges" under the same node.
5. Apply, then gpupdate /force.
6. Re-run setup.exe.

This path is acceptable only when the STARTER install is the lone MSI in flight. If another package is mid-transaction, suppressing the check can corrupt the install.

7. Solution 3: Install on a Supported Operating System

Siemens' official recommendation in the support thread is to install STARTER on a supported OS. While engineers often inherit Windows 8 laptops and want to avoid provisioning a second machine, the supported-OS path is the lowest-risk option:

For VM deployment, allocate at least 2 vCPU, 4 GB RAM, and a fixed 60 GB virtual disk. Enable USB Controller with the xHCI mode if the SIMATIC USB cable is in use; legacy EHCI controllers will hang on Windows 8.1 VMs.

8. Solution 4: Migrate to Startdrive / TIA Portal

STARTER has been officially replaced by Startdrive, the integrated commissioning option inside the TIA Portal. New SINAMICS projects should be created in Startdrive where possible. Migration is not always mandatory, but it eliminates the Windows 8 install loop because Startdrive V15.1 supports Windows 7 SP1, Windows 10 (1607+), and Windows Server 2016/2019.

1. Install TIA Portal V16 or V17 (whichever matches your STEP 7 baseline).
2. Open the TIA Portal and select Options → Startdrive.
3. Insert a new SINAMICS S120 device from the catalog.
4. Use Project → Migrate STARTER project to import legacy .zip archives from STARTER V4.4 / V5.x.
5. Review the migration log. DCC (Drive Control Chart) graphs require manual verification; the migrator reports the number of unsupported blocks.

Startdrive preserves the parameter numbering convention (Pxxxx, rxxxx) but introduces the TIA Portal concept of devices and networks. Drives now appear as devices under the PLC or HMI station rather than as standalone offline objects.

9. Verification Steps

After a successful install, verify that STARTER can communicate with a physical or simulated SINAMICS drive:

1. Launch STARTER. The expected splash should display SIMATIC STARTER — V4.4 HF3 (or your installed version).
2. Create a new project: Project → New → Offline → Empty project.
3. Insert a SINAMICS S120 device tree: Insert → Drive → SINAMICS S120.
4. Connect the PC to the drive via PROFINET, PROFIBUS, or Ethernet (for CU320-2 PN with IP 169.254.11.22).
5. Set the PG/PC interface: Options → Set PG/PC interface → S7ONLINE (STEP7) → TCP/IP → <your NIC>.
6. Right-click the drive in the project tree and select Online → Connect to target system.
7. The drive's online identifier (e.g. S120_CU320_2_PN_001) should appear with a green status icon.
8. Click Online → Load to PG to read parameters. Confirm parameter r0002 (drive status word) reads back correctly.
9. Disconnect cleanly: Online → Disconnect.

If Connect to target system fails with timeout, check:

• The NIC IP is in the same subnet as the CU (default 169.254.x.x).
• Windows Firewall allows SIMATIC_STARTER.exe and S7oiehsx.exe on the Domain and Private profiles.
• The PROFINET cable is pinned correctly (TIA-568B on both ends; crossover only needed for direct PC-to-CU without a switch).
• The CU is in commissioning mode (DIP switch on CU320-2 PN set to "Profibus address 0" or "No address").

10. Troubleshooting Matrix

11. Compatibility Matrix: STARTER vs. Startdrive vs. SINAMICS Firmware

The compatibility claims above are summarized from Siemens' STARTER and Startdrive readme documents. Always cross-check against the specific delivery release notes shipped with the product DVD, because Siemens has revised platform support between service packs without changing the public catalog number.

12. Field-Proven Best Practices

• Always run STARTER as Administrator. The MSI engine on UAC-enabled systems will route the install to %LOCALAPPDATA%\VirtualStore\Program Files (x86)\Siemens if the token is not elevated, leaving the actual %ProgramFiles(x86)% install empty and causing subsequent launch failures.
• Snapshot before install. If the engineering workstation is a VM, take a snapshot before and after a successful STARTER install. A corrupted STARTER install is faster to roll back than to surgically clean.
• Avoid parallel SINAMICS tools. Do not install SIMATIC Manager, TIA Portal, SCOUT, and STARTER on the same image. They share S7oiehsx.exe and conflicting versions of the OPC server (SINEC). Use separate images for each commissioning ecosystem.
• Keep install media offline. Siemens' DVD images are large (typically 3.2 to 6.5 GB). Run the install from a local copy, not a network share, to avoid MSI source path issues.
• Disable hibernation, not just sleep. Windows 8 hibernation preserves file handles that the installer may interpret as "files in use". Run powercfg /hibernate off before large installs.
• Keep %TEMP% clean. InstallShield unpacks to %TEMP%\{GUID}. A full %TEMP% (less than 2 GB free) can cause the bootstrapper to think the install failed and re-prompt for a reboot.

13. When to Escalate to Siemens Support

Escalate to Siemens Industry Online Support if any of the following are true after applying Solutions 1 through 3:

• STARTER installs but immediately crashes with an unhandled exception in STARTER.exe or s7otbldx.dll.
• The MSI log (%TEMP%\STARTER_Setup.log) shows error 1719 (Windows Installer service could not be accessed) repeatedly.
• Drive firmware is newer than any STARTER/Startdrive release supports (current cutoff: SINAMICS V6.x requires Startdrive V18 SP1+).
• The project contains DCC graphs referencing DCB libraries that are no longer shipped (typical when commissioning legacy S120 systems from 2008-2012).

When escalating, attach the install log, the contents of PendingFileRenameOperations (if any), the Windows event log Application channel filtered to source MsiInstaller, and the output of msinfo32 /report. Siemens' support analysts can match these against known issues database (KID) entries.

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