How do I fix FSX Acceleration error 1-80004005?

FSX Acceleration error 1-80004005 usually means boxed FSX cannot complete its hardware-based activation check. Restore PartMgr in the disk-class UpperFilters registry value, restart Windows, then run FSX as administrator and activate the base simulator before Acceleration. Do not apply this retail activation fix to FSX: Steam Edition.

Why does FSX Acceleration show error 1-80004005?

The code is a generic failure returned by the activation component, but its best-known FSX cause is a missing PartMgr entry in the Windows disk-drive class registry key. FSX uses that component while creating or checking its licence state, so a valid product key can still fail before it is properly processed.

Storage software, registry cleaners and operating-system changes can alter filter entries. Do not follow unrelated Windows advice for the similarly written 0x80004005 error; the FSX Acceleration activation context matters here.

Restore the PartMgr registry value

Adding PartMgr back normally resolves this particular boxed-FSX activation error. Registry mistakes in this area can affect disk access, so preserve every existing entry and edit only the key shown below.

1. Confirm that you have boxed FSX. This procedure is for the DVD editions of FSX, FSX Gold and Acceleration, not FSX: Steam Edition.
2. Back up the registry key. Create a Windows restore point, open Registry Editor as administrator, select the key identified in the next step and use its Export command to save a copy.
3. Open the disk-drive class key. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318}.
4. Inspect UpperFilters. If the value exists, open it and check whether PartMgr is present. If it is missing, add PartMgr on a separate line without removing or replacing any other entries.
5. Create the value only if it is absent. Create a Multi-String Value named UpperFilters, then set its data to PartMgr. Do not create an ordinary String Value and do not alter a similarly named value under another class identifier.
6. Restart Windows. The filter change is not fully loaded until the computer has restarted.
7. Activate in the correct order. Run FSX as administrator once, complete activation of the base simulator, then activate Acceleration with the separate Acceleration key when prompted.

What if PartMgr is already present?

If PartMgr is already listed, leave the registry unchanged. The next likely causes are the wrong product key, an incomplete installation, incorrect update order or a conflict between retail and Steam files.

• Check the key: boxed FSX and Acceleration use different product keys. If the key itself is rejected, follow our checks for matching each retail key to the correct FSX product and repairing its licence state.
• Check the installation sequence: the base simulator must be installed and activated before Acceleration. Our boxed FSX and service-pack installation order explains which updates belong before and after Acceleration.
• Keep editions separate: do not install the boxed Acceleration expansion over FSX: Steam Edition. Steam Edition already incorporates Acceleration-era content and does not use the retail Acceleration activation process.
• Run once as administrator: this lets the legacy activation component write its licence data. Permanent administrator or compatibility settings should not be necessary once activation succeeds.

On Windows 11, an activation attempt may instead produce an expired or out-of-date licence message. That needs the separate Windows 11 boxed-FSX licence repair procedure, not repeated changes to UpperFilters.

Will reinstalling FSX Acceleration fix the error?

Reinstallation usually will not fix error 1-80004005 when PartMgr is missing, because that value belongs to Windows rather than the FSX installation folder. Repair the registry value first.

Reinstall only when Acceleration setup rolled back, files are missing or the activation prompt never appeared. In that case, use the targeted steps for repairing FSX Acceleration setup failures, restart between installation stages and keep any Steam installation separate from the boxed edition.