Resolving Siemens Scout DeIsL.isu Missing File Uninstall Error

1. Problem Overview

Engineers performing platform migrations, drive commissioning tool standardization, or clean operating-system rebuilds frequently encounter a stubborn uninstall blocker in Siemens SIMOTION Scout V4.1.1.0 (and adjacent 4.1.x builds). The deinstallation routine aborts with an error referencing a missing DeIsL.isu file, leaving the SIMOTION Scout entry in the Windows Programs and Features applet (Add/Remove Programs) but with no working removal path. This blocks subsequent installation of SINAMICS Starter, the standalone commissioning tool for SINAMICS S110/S120 drive lineups.

The failure is a typical artifact of an interrupted uninstallation: power loss, manual termination of the MSI process, disk full condition, or a crashed InstallShield script leaves orphaned registry entries and a half-removed installation tree. The remaining DeIsL.isu (InstallShield uninstallation script) is either deleted with the partial uninstall or never copied in the first place when the source media was incomplete.

2. Affected Software Versions and Components

The uninstall blocker is reproducible on the following Siemens software stacks:

For Siemens lifecycle reference of SIMOTION Scout, see the SIMOTION SCOUT entry on Siemens Industry Online Support. SINAMICS Starter product information is published at the SINAMICS Starter support entry.

3. Root Cause Analysis

The DeIsL.isu file is the InstallShield uninstallation script generated when the original SIMOTION Scout installation wrote the InstallShield Installation Information registry key under:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{GUID}_is1
    DisplayName    = SIMOTION Scout
    UninstallString = "C:\Program Files\Step7\U7umc\DeIsL1.isu" -runfromtemp -l0x0007 -removeonly
    InstallLocation = C:\Program Files\Siemens\Automation\Scout
    DisplayVersion = 4.1.1.0

The UninstallString value points to DeIsL1.isu (or DeIsL.isu on older revisions), which contains the rollback instructions for every file copied, registry key written, and service registered by the Scout installer. When Windows attempts to honor the Programs and Features removal request, the InstallShield runtime:

1. Reads the UninstallString from the registry.
2. Invokes ISBEW64.exe (or ISBEW32.exe) with the -f parameter pointing to the .isu file.
3. Executes the rollback sequence defined in DeIsL.isu.

Error 1723: There is a problem with this Windows Installer package.
A DLL required for this install to complete could not be run.
Contact your support personnel or package vendor.

- or -

InstallShield Silent execution:
Could not find InstallShield script file:
C:\Program Files\Step7\U7umc\DeIsL1.isu

The orphaned registry entry then persists, blocking both repair and removal, and the MSI engine refuses subsequent installations that target the same product code because the installed-product state is "broken."

4. Prerequisites for Recovery

Before attempting the recovery procedure, verify the following prerequisites:

1. Local administrator rights on the target workstation. The U7UMC directory and the HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall hive both require elevation.
2. Original installation media for SIMOTION Scout V4.1.1.0 (DVD image or extracted ISO), or an equivalent source path containing the DeIsL.isu / DeIsL1.isu archive. If the original media is not available, request the file from a peer workstation with a healthy installation.
3. Step 7 installation intact. Verify C:\Program Files\Step7\U7umc exists and is writable. If Step 7 itself is damaged, repair it via the Step 7 setup before attempting Scout recovery.
4. No pending reboots. Run shutdown /r /t 0 if Windows reports pending file rename operations from a prior interrupted install.
5. Backup the registry hive before any edits. Export HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall to C:\Backup\Uninstall.reg.

5. Step-by-Step Recovery Procedure

5.1 Locate a valid DeIsL.isu / DeIsL1.isu

The uninstall script is the same file delivered with the original SIMOTION Scout media. It is typically located in the source media under:

D:\Setup\SCOUT\V4.1\Setup\DeIsL.isu
D:\Setup\SCOUT\V4.1\DeIsL1.isu
- or -
C:\Siemens\Install\Scout\V4.1.1\DeIsL.isu

If the media is not available, search any peer workstation where SIMOTION Scout V4.1.x is healthy. The file is located at:

C:\Program Files\Step7\U7umc\DeIsL.isu
C:\Program Files\Step7\U7umc\DeIsL1.isu

The file is small (typically 32 KB to 256 KB) and is byte-identical across installs of the same patch level. Copy it via a removable drive, network share, or secure file transfer to the affected workstation.

5.2 Place the file in the U7UMC directory

1. Open an elevated command prompt (Run as Administrator).
2. Verify the target directory exists:

   dir "C:\Program Files\Step7\U7umc"

3. Copy the recovered file into the directory. Preserve the original filename exactly as referenced in the UninstallString registry value:

   copy DeIsL1.isu "C:\Program Files\Step7\U7umc\"
   - or -
   copy DeIsL.isu "C:\Program Files\Step7\U7umc\"

4. Verify the file size and timestamps match the source.

5.3 Re-register the InstallShield runtime

If the InstallShield runtime itself was uninstalled or damaged, re-register it before retrying:

cd /d "C:\Program Files\Common Files\InstallShield\Driver\<version>\Intel 32"
regsvr32 /s IDriver.exe
- or for 64-bit hosts -
cd /d "C:\Program Files (x86)\Common Files\InstallShield\Driver\<version>\Intel 32"
regsvr32 /s IDriver.exe

5.4 Invoke the deinstallation routine

1. From the elevated command prompt, run the uninstall string exactly as stored in the registry. Read the value first:

   reg query "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall" /s /f "SIMOTION Scout"

2. Locate the UninstallString value for the SIMOTION Scout entry. It will resemble:

   "C:\Program Files\Step7\U7umc\DeIsL1.isu" -runfromtemp -l0x0007 -removeonly

3. Execute the uninstall string directly:

   "C:\Program Files\Step7\U7umc\DeIsL1.isu" -runfromtemp -l0x0007 -removeonly

4. Follow the interactive prompts. The InstallShield runtime will run the rollback sequence defined in the .isu file and remove Scout, the associated add-ons, and the registry entries.

5.5 Clean up residual registry entries

After the deinstallation completes, verify the registry is clean:

reg query "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall" /s /f "SIMOTION Scout"
reg query "HKLM\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall" /s /f "SIMOTION Scout"

Both queries should return no results. If any entries remain, manually delete them after exporting the hive for safety:

reg delete "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{GUID}_is1" /f
reg delete "HKLM\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\{GUID}_is1" /f

5.6 Install SINAMICS Starter

With Scout cleanly removed, install Starter from the SINAMICS commissioning DVD or Siemens download portal. Confirm the installer completes without MSI error 1719 ("Error opening installation package") or error 1723 ("DLL required for this install to complete could not be run"), both of which would indicate the registry state is still corrupted.

6. Scout vs Starter: Functional Comparison

Engineers often pursue the uninstall because they assume Starter is required for their use case. Before completing the recovery, verify whether the integrated Starter functionality in SIMOTION Scout V4.1+ already meets the requirement. For SINAMICS S110/S120 drive commissioning with CU310 or CU320 control units, Scout V4.1+ embeds a full Starter commissioning environment.

For deployments focused exclusively on drive commissioning with no SIMOTION controller, Starter standalone reduces installer footprint and avoids the Step 7 / U7UMC dependency that produces this uninstall failure. For mixed SIMOTION + SINAMICS deployments, retaining Scout and using the integrated Starter engine eliminates the need for two parallel commissioning tools.

7. Verification Steps

After completing the recovery and (optionally) installing Starter, perform the following verification sequence to confirm a clean state:

1. Programs and Features check. Open Control Panel → Programs and Features (Windows 7) or Settings → Apps & Features (Windows 10). Verify "SIMOTION Scout" is absent.
2. Registry check. Confirm no residual {GUID}_is1 entries remain under either 32-bit or 64-bit uninstall hive.
3. Directory check. Confirm C:\Program Files\Siemens\Automation\Scout is absent or empty. Step 7 may leave U7UMC with residual Scout add-on DLLs; these are harmless and can be cleaned with a Step 7 repair install.
4. Service check. Run sc query | findstr /i "siemens scout". No residual Scout services should be listed.
5. Starter functional check. Launch Starter, open an existing project or create a new offline project, and verify the project tree loads without COM object errors.
6. Drive online check (if hardware available). Connect to a CU320/CU310, perform an online connection, and verify the parameter list downloads correctly.

8. Alternative Path: Keep Scout and Use the Integrated Starter

If the underlying motivation for removing Scout is simply to gain access to Starter functionality for drive commissioning, the uninstall may be unnecessary. SIMOTION Scout V4.1+ includes an integrated SINAMICS Starter engine that:

• Opens the same *.dnx / *.sin drive projects as standalone Starter.
• Supports online connection to CU310, CU320, CU305, CU240S, and other SINAMICS control units via PROFIBUS, PROFINET, and Ethernet.
• Provides identical parameter editor, trace, and function generator capabilities.
• Exports drive projects to *.ds archives compatible with standalone Starter.

To access the integrated Starter from Scout V4.1.1.0:

1. Launch Scout and open the project navigator.
2. Right-click the SIMOTION controller or SINAMICS drive element.
3. Select Commissioning → Starter from the context menu, or navigate to the SINAMICS sub-tree and double-click the drive object.
4. The integrated Starter panel opens inline within Scout, providing drive parameterization without launching a separate application.

This eliminates the uninstall requirement entirely and reduces the chance of further registry corruption.

9. Troubleshooting Matrix

10. Related Issues and Edge Cases

10.1 Multiple Scout versions installed simultaneously

Engineering workstations occasionally have multiple Scout versions installed side-by-side (e.g., V4.1.1.0 for legacy projects and V4.4 for new ones). Each version installs its own DeIsL*.isu in U7UMC. When removing an older version, verify the UninstallString GUID matches the specific .isu file to avoid accidentally triggering the rollback of a different version.

10.2 Windows 10 / 11 compatibility

SIMOTION Scout V4.1.x was designed for Windows XP and Windows 7. On Windows 10 and 11, the InstallShield runtime may exhibit additional error paths due to UAC virtualization changes and WOW64 redirection. Running the recovery procedure on a Windows 7 host or in a Windows 7 compatibility VM is recommended when the production target must remain on a current Windows version.

10.3 Virtual machine rollback

Before attempting the recovery, snapshot the VM if Scout is installed in a virtualized engineering workstation. This provides a single-step rollback if the recovery procedure corrupts the registry beyond manual repair.

10.4 Silent / unattended uninstall

For fleet deployments, the recovery can be scripted. The following batch sequence performs the file restore and uninstall in an unattended fashion:

@echo off
REM Restore DeIsL1.isu from network share
net use Z: \\fileserver\siemens$
copy /Y Z:\Scout\V4.1\DeIsL1.isu "C:\Program Files\Step7\U7umc\" /R

REM Re-register InstallShield runtime
cd /d "C:\Program Files (x86)\Common Files\InstallShield\Driver\1150\Intel 32"
regsvr32 /s IDriver.exe

REM Execute silent uninstall
"C:\Program Files\Step7\U7umc\DeIsL1.isu" -s -f1"C:\Logs\Scout_Uninstall.iss" -removeonly

REM Cleanup residual registry
reg delete "HKLM\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\{SCOUT_GUID}_is1" /f

REM Install Starter silently
D:\Starter\Setup.exe /s /v"/qn REBOOT=ReallySuppress REINSTALLMODE=vomus"

REM Reboot if required
if exist C:\NeedsReboot.flag shutdown /r /t 0

10.5 STEP 7 V5.5 vs TIA Portal interference

If TIA Portal V13 or later is installed alongside STEP 7 V5.5, the SIMOTION Scout V4.1.x deinstallation can interfere with TIA Portal's project storage locations under C:\Program Files\Siemens\Automation\. Take a registry backup and review TIA Portal project accessibility after the recovery completes. For TIA-native SIMOTION commissioning, upgrade to SIMOTION Scout TIA (V5.x) which integrates with TIA Portal and avoids the Step 7 V5.5 dependency that triggers this failure class.

11. FAQ