What is one reason a memory upgrade might fail to function correctly?

A memory upgrade might fail to function correctly for several reasons, and compatibility is a critical factor. When the memory is not compatible with the motherboard or other hardware components, the system cannot recognize or utilize the new memory effectively. This incompatibility could arise from differences in memory type, speed, or form factor (such as DIMM versus SO-DIMM).

If the memory module does not match the specifications required by the motherboard, it may either not work at all or may lead to system instability, crashes, or failure to boot. This is why ensuring that the memory upgrade is compatible with the system's specifications is essential for a successful installation.

The other options highlight aspects of installation and hardware capability but do not directly relate to the core issue of compatibility. Proper installation and sufficient power supplies are critical, but they do not address the most common root cause of failed memory upgrades, which is a lack of compatibility between the components.