I usually download from here:
https://www.microsoft.com/en-us/wdsi/defenderupdates
But it was odd that the page showed the wrong date:

I also tried to download from here:
How to manually download the latest definition updates for Microsoft Security Essentials - Microsoft Support
but that gave a message "Page Not Found".
- - - Updated - - -
Loos like the problem has been fixed.
https://www.microsoft.com/en-us/wdsi/defenderupdates
But it was odd that the page showed the wrong date:

I also tried to download from here:
How to manually download the latest definition updates for Microsoft Security Essentials - Microsoft Support
but that gave a message "Page Not Found".
- - - Updated - - -
Loos like the problem has been fixed.
My Computer
- Computer type
- PC/Desktop
- Computer Manufacturer/Model Number
- refurb in an HP/Compaq case
- OS
- Windows 7 Ultimate x64
- CPU
- 1.86 GHz Intrel Core 2
- Motherboard
- HP 0A60h XU1
- Memory
- 3 GB Dual Channel DDR2 @ 3.32 MHz
- Graphics Card(s)
- Intel Q965/Q963 Express chipset
- Monitor(s) Displays
- Dell CRT
- Hard Drives
- 977GB Samsung HD 103 SI ATA
- Case
- HP Compaq DC5800
- Mouse
- wired optical
- Antivirus
- Microsoft Security Essentials, MalwareBytes, Spyware Blaster
- Browser
- Firefox 32-bit