How do I fix FSX Acceleration error code 1: 0x80004005?

FSX Acceleration error 1: 0x80004005 usually means the boxed edition cannot complete its hardware-based activation check because PartMgr is missing from the disk-class UpperFilters registry value. Restore that entry without deleting existing filters, restart Windows, then activate base FSX before Acceleration. This fix does not apply to FSX: Steam Edition.

Why does FSX Acceleration show error 1-80004005?

In this FSX context, error 0x80004005 is a generic failure from the legacy retail activation system, commonly caused by a missing PartMgr disk filter entry. The activation check can therefore fail before it properly processes a valid product key.

The registry class identifier {4D36E967-E325-11CE-BFC1-08002BE10318} represents Windows disk drives. PartMgr is the Microsoft partition-manager filter used by the hardware-based check. Storage utilities, registry cleaners and operating-system changes can remove or replace filter entries.

Is the PartMgr registry fix right for my FSX edition?

Use this registry repair only for a boxed or DVD copy of Microsoft Flight Simulator X and its retail Acceleration expansion.

If the edition or installation order is unclear, use our boxed FSX Acceleration installation sequence for modern Windows before changing the registry.

How do I restore PartMgr under {4D36E967-E325-11CE-BFC1-08002BE10318}?

The safe repair is to preserve every existing disk filter and add only the missing PartMgr entry. Editing the wrong disk-class value can interfere with storage access, so export the key first and make sure any device-encryption recovery information is available.

1. Confirm the edition. Continue only if this is boxed FSX, FSX Gold or the retail Acceleration expansion. Close FSX and its installer.
2. Create a backup. Make a Windows restore point, open Registry Editor as an administrator and export the class key before editing it.
3. Open the exact disk-drive class key. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318}. Use the class key itself, not one of its numbered subkeys. This location is the same on 64-bit Windows; do not look under Wow6432Node.
4. Inspect UpperFilters. In the right-hand pane, find UpperFilters. Its type should be REG_MULTI_SZ, which Registry Editor describes as a Multi-String Value.
5. Add PartMgr without replacing anything. If UpperFilters exists and PartMgr is absent, add PartMgr on its own line. Preserve every existing entry exactly as shown, and do not add a duplicate if it is already present.
6. Create the value only when it is completely absent. Create a new Multi-String Value named UpperFilters and set its data to PartMgr. Do not create an ordinary String Value.
7. Stop if the registry structure is abnormal. Do not fabricate the class key if the GUID is missing, and do not casually delete an UpperFilters value of another type. Those conditions suggest a wider Windows storage configuration problem.
8. Restart Windows. A full restart is required before the disk filter configuration is reloaded.
9. Retry activation as administrator. On an existing Acceleration installation, run FSX once using Run as administrator and retry the prompt. For a clean installation, run and activate base FSX before installing and activating Acceleration.

Do not stack service packs indiscriminately around Acceleration. Our guide to when SP1 and SP2 belong in a boxed-FSX installation explains the difference between updating base FSX and installing Acceleration. With Gold media, follow the Deluxe-then-Acceleration recovery order for FSX Gold.

Do error 8000x4005 and 0x80004oo5 mean the same thing?

8000x4005, 08000x4005 and 0x80004oo5 are usually mistyped versions of 0x80004005. The correct hexadecimal notation places the x after the first zero and uses zeroes, not the letter “o”. Check the actual FSX dialogue before applying any repair; the boxed-activation message is commonly written as Error Code: 1-80004005.

Can a valid product key still produce error 0x80004005?

Yes. A genuine key can fail with error 0x80004005 when the activation component cannot complete its hardware check, so the error alone does not prove that the key is invalid.

Boxed base FSX and Acceleration have separate activation keys, and one cannot be substituted for the other. A search may also surface instructions involving a registry value called ValidProductKey; do not create or change that value for this fault. It is not a replacement product key and does not restore the missing disk filter.

If the dialogue specifically reports an invalid key, an activation limit or an unavailable activation service rather than error 1-80004005, follow the options shown by that dialogue. Repeatedly editing UpperFilters will not resolve a key- or service-specific rejection.

What if PartMgr is already present?

If PartMgr is already listed in the correct Multi-String Value, leave it unchanged and do not add a second copy. The generic error must then be narrowed down by its exact timing and message.

• Run FSX as administrator once: the old activation component may need elevated permission to write its licence state. Permanent administrator or compatibility settings should not be needed after successful activation.
• Check the requested key: make sure the prompt is for base FSX or Acceleration and use the corresponding key from that boxed product.
• Check for mixed editions: retail Acceleration must not be installed over FSX: Steam Edition, nor should retail and Steam files be merged into one installation.
• Check setup completion: a rolled-back Acceleration setup, missing files or an installer that never reached activation is an installation failure rather than a PartMgr problem.
• Read the whole message: errors mentioning damaged media, Windows Installer or a numbered setup code need an installer repair, not further changes to the disk-class registry.

Will reinstalling FSX Acceleration fix error 1-80004005?

Reinstalling FSX Acceleration normally does not fix this error when PartMgr is missing, because the affected value belongs to Windows rather than the FSX installation folder. Repair the value and restart first.

Reinstall only when setup rolled back, files are missing or the activation prompt never appeared. In that situation, use the targeted checks for repairing failed FSX Acceleration installations, and keep every boxed installation separate from FSX: Steam Edition.