Windows 95 startup behavior — What file extension does Windows 95 use for its automatic backup copy of the Registry at startup?

Introduction / Context:
Understanding legacy Windows startup files is useful when recovering older systems or studying OS history. Windows 95 maintained Registry data and created backup copies during startup for recovery.

Given Data / Assumptions:

• Platform: Microsoft Windows 95 (pre-ScanReg daily .cab backups used by later versions).
• Registry core files include System.dat and User.dat.
• Question concerns the extension of the startup backup copy.

Concept / Approach:

Windows 95 creates fallback copies of Registry hives using a conventional backup extension. While the active hives use .dat, backups are commonly stored using the .bak extension to indicate a restorable previous state.

Step-by-Step Solution:

Verification / Alternative check:

Legacy troubleshooting guides and Windows 95 references describe replacing corrupted .dat files with their .bak counterparts when repairing the system.

Why Other Options Are Wrong:

.dat are active Registry files, not the backup extension. .dao and .tmp are unrelated; “None of the above” is incorrect because .bak is correct.

Common Pitfalls:

Confusing Windows 95 behavior with Windows 98/ME ScanReg .cab restore points; assuming .tmp holds reliable backups.

Final Answer:

.bak.