Recovering a Siemens WinCC V5.1 RT256 Multi-Authorization License Disk After PC Failure

This technical reference documents the recovery workflow for a Siemens SIMATIC WinCC V5.1 SP2 system whose host PC has failed and whose RT 256 PowerTags multi-authorization floppy (MLFB 6AV6381-1BD05-1CX0) returns the Windows error "Do you want to format it now?" The same procedure applies to the closely related WinCC V5.0 and V5.2 RT licenses and to the older Multi-Authorization Disk Plus (MAD Plus) format. Engineers responsible for plant-floor SCADA recovery on Windows 2000 / Windows NT 4.0 will recognize the symptom set: an inaccessible 3.5" license floppy, a hidden AX NF ZZ folder, fourteen-day emergency licenses surfacing from the wrong disk, and a final Autostart not possible fault at WinCC runtime startup.

1. Symptom Matrix

2. Affected Components and Identifiers

3. Root Cause: Why the License Disk Looks "Unformatted"

The WinCC Multi-Authorization Disk is not a standard FAT12 floppy. It is a specially formatted disk that holds one or more SIK (Software Identification Key) records signed by the Siemens license server. The disk contains, in raw sectors, the cryptographic blob that AuthorsW translates into a usable license key on the local hard drive. Windows 2000's 32-bit file system recognizer cannot parse the layout, so the shell displays the legacy "Do you want to format it now?" dialog. The disk is not corrupt from the OS perspective; it is simply an unknown volume.

When AuthorsW is launched and drive A: is selected, AuthorsW reads the disk through its own low-level routine. If AuthorsW then reports "A:\ cannot be accessed, Device is not ready", the floppy media itself is degraded (magnetic oxide failure, dirty heads, or a defective mechanical shutter). In that case AuthorsW will continue to display the five 14-day emergency licenses from whatever other SIK source it can find on the system, but the original full keys are unrecoverable from the damaged disk.

A further subtlety: the same five SIK entries may appear on the Step 7 license disk, on the WinCC emergency-license disk, and inside the AuthorsW pane when no disk is inserted at all. This is by design. Siemens pre-loads a generic emergency-license set into the local SIK store C:\"AX NF ZZ" so that a developer can always boot WinCC for fourteen days. Those 14-day keys are not the same as the permanent RT 256 PowerTags authorization; they will expire and the project will refuse to activate.

4. AuthorsW: The Only Tool That Can Read the Disk

AuthorsW is the Siemens authorization management utility bundled with every WinCC installation CD and with the SIMATIC NET PC software CD. It performs three jobs:

1. Reads the Multi-Authorization Disk and transfers the signed SIK blobs to the local license store.
2. Displays every active license on the hard drive.
3. Imports emergency licenses (typically valid 14 days) when no permanent key is available.

AuthorsW must be installed before any license disk is touched. It is the only application that can interpret the proprietary disk format. Inserting a Multi-Authorization Disk into a system without AuthorsW and then clicking through the format prompt is the single most common cause of permanent license loss in legacy WinCC installations.

5. License Storage on the Hard Drive

Once AuthorsW successfully reads a Multi-Authorization Disk, it copies the SIK blobs into a hidden system folder on the boot drive:

C:\"AX NF ZZ (note the literal spaces between the quote pairs)

This folder is hidden, system, and read-only by default. It is the single source of truth for which WinCC / STEP 7 / SIMATIC NET features will activate on that machine. If this folder is missing, defragmentation has re-clustered the file extents, or the drive has been re-imaged, AuthorsW will fall back to the 14-day emergency keys and the system will appear to be licensed but will refuse to start after the trial expires.

Recovery strategy: never defragment or image the boot drive while WinCC is licensed on it. If you must image, capture the AX NF ZZ tree separately and re-inject it after restoring the image.

6. Step-by-Step Recovery Procedure

The following sequence is verified against the Windows 2000 + WinCC V5.1 SP2 + SIMATIC NET V6.0 + SP5 + HF2 stack described in the source scenario. Adapt the version numbers but not the order.

1. Image the failing PC's hard drive with a sector-level tool (e.g., dd, Ghost, or a USB dock clone) before powering it off. The license may still be present in AX NF ZZ even if the disk does not boot.
2. Install Windows 2000 from the OS CD. Apply the service packs in the documented order: W2KSP4 (S79220-A7014-F000-01) last, after WNtSP6a (S79220-A6046-F000-01) if migrating from NT 4.0. Both are part of the cumulative update chain and the order must not be reversed.
3. Install Internet Explorer 6 (required by WinCC V5.x Web Navigator components and by some setup dialogs).
4. Install Microsoft Tools for WinCC (the pre-flight check package that validates DCOM, OPC, and account privileges).
5. Install SIMATIC NET PC software V6.0 + SP5 + HF2 (S79220-A6649-F000-01). This CD carries the AuthorsW executable. Confirm the Start menu entry Simatic → AuthorsW exists before continuing.
6. Insert the WinCC V5.1 SP2 setup CD. Do not have any license floppy in drive A: during setup. Let setup complete and reboot.
7. Insert the WinCC RT 256 PowerTags Multi-Authorization Disk (6AV6381-1BD05-1CX0) into drive A:. Launch Simatic → AuthorsW. AuthorsW should now list the full RT 256 PowerTags license, not the 14-day emergency entries. If the disk is still unreadable, skip to Section 9 for hotline escalation.
8. Launch Simatic → WinCC Explorer. Open the project file ZAR_WinCC.MCP from its original folder. If the project was on a removable drive, verify that drive is mounted at the same letter (D: in this case) and that the path D:\<project>\ZAR_WinCC.MCP resolves.
9. Edit the project startup settings: enable Activate Project at startup and Accept cancel during activation. Save.
10. Reboot. Watch for the messages Searching for modified SIMATIC NET hardware, then the Station Configuration Editor window, then AutoStartRT.
11. If AutoStartRT ends with Autostart not possible, proceed to Section 7.

7. Resolving the "ZAR_WinCC.MCP Autostart not possible" Fault

The Autostart not possible dialog appears when WinCC runtime can load the project database but cannot complete one of the prerequisite handshakes. Investigate in the following order:

1. SIMATIC NET station configuration. Open Simatic → Station Configurator and confirm the PC station name matches the project. Re-import the XDB file from the project folder if it has drifted. Without a valid station, the S7 / S5 channel will not bind and runtime will refuse to start.
2. Project path inside the registry. AuthorsW and the WinCC autostart hook both read the project path from HKLM\SOFTWARE\Siemens\WinCC\<version>\ProjectPath. If the project lived on drive D: and the new image has only a C: partition, the registry still points at D: and runtime cannot find the .MCP file even though Windows Explorer can. Update the registry or move the project to the expected path.
3. License at runtime. Start the WinCC project manually from WinCC Explorer (not from AutoStartRT) with the 14-day emergency license still active. If the project opens, the license is sufficient and the autostart fault is a path or station issue, not a license issue. If it refuses, the permanent license has not been transferred to AX NF ZZ; re-run AuthorsW with the multi-authorization disk in drive A:.
4. User account. WinCC V5.x runtime must run under an account that is a member of the local SIMATIC HMI group and has the Log on as service right. The default Administrator account satisfies this; a renamed or limited account does not. If the source PC used a custom account, recreate it identically.
5. DCOM and OPC. Run the Microsoft Tools for WinCC pre-flight checker. Any red item must be cleared before runtime will autostart.

Once the manual launch succeeds, retry the autostart. The dialog should not reappear.

8. Long-Term Migration Path: WinCC 5.x to WinCC 6.2

Siemens support has confirmed that a WinCC V5.2 project can be migrated directly to WinCC V6.2 using the Project Migrator. The migration is a one-way operation; the source project must remain intact until the migrated copy is verified. To perform the migration:

1. Install WinCC V6.2 on a separate PC or partition. Insert the V6.2 installation CD and add the optional Project Migrator component.
2. Insert the original WinCC V5.2 installation CD when prompted; the migrator needs the V5.2 setup binaries to translate legacy tag names and picture formats.
3. Point the migrator at the .MCP file. The tool produces a new V6.2 project directory and a migration log. Read the log line by line; every warning about deprecated tag types or unsupported ActiveX controls must be resolved before commissioning.
4. Validate the migrated project in runtime against a simulated PLC. Do not deploy a migrated project to a live plant without this step.

Migration does not transfer licenses. The RT 256 PowerTags authorization from the V5.x disk is not valid on a V6.2 system. A new V6.2 license (or a V6.2 compatibility license purchased from Siemens) must be installed after migration.

9. When the Multi-Authorization Disk Itself Has Failed

If AuthorsW persistently reports Device is not ready on drive A:, the floppy media is no longer recoverable by software. Do not attempt the following: reformat, image with a sector tool, dd the disk, magnetize, or heat. None of these will restore a signed SIK blob; they will only accelerate its destruction.

The correct escalation path is the Siemens Authorizations Hotline. Open a support request with the original Certificate of License (CoL) in hand. The hotline needs the SIK serial number, the MLFB of the original disk, and the CoL number. With those three items they can issue a replacement authorization. The official entry point is documented in Siemens support entry ID 772175 (Authorizations / License Key replacement). Expect a per-incident processing fee and proof of original purchase.

For plant-floor engineers who cannot reach the hotline during a recovery window, the 14-day emergency license is the legal fallback. Document the start date in the plant log, schedule the production-critical screens to be saved to a non-volatile location, and plan the replacement before day 13. WinCC will refuse to start the project on day 15 if no permanent key is present.

10. Commissioning Verification Checklist

11. Prevention: Image the License, Not Just the Disk

After recovery, before the system returns to production service, capture both the Multi-Authorization Disk (a raw .img written to a USB stick) and the C:\"AX NF ZZ tree (a robocopy /MIR from an elevated command prompt that preserves hidden and system attributes). Store both on the plant's standard backup medium. This pair is the smallest unit that can fully restore WinCC licensing on a fresh machine. The original disk itself can then be locked in the engineer's safe, untouched, and used only when an identical license must be installed on a second engineering station.

Additional preventive measures:

• Disable Windows defragmentation on the WinCC boot drive. Defragmenting moves the SIK file extents and can corrupt the cryptographic chain.
• Disable System Restore on Windows 2000 / XP SCADA stations. Restore points roll back the license folder and trigger the 14-day emergency state.
• Document the CoL number, SIK serial, and MLFB on a label attached to the PC chassis. License replacement requires all three and they are easy to lose when the original paperwork is filed off-site.
• For redundant SCADA pairs, maintain identical license sets on both PCs. AuthorsW will refuse to install the same SIK on two machines unless the original disk is physically present; keep one license floppy per machine.

12. Frequently Asked Questions