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Windows 7: What is this 3GB file? MSSDMC?

29 Jan 2010   #1

Windows 7 Ultimate 32 and 64 bit
What is this 3GB file? MSSDMC?

There's this huge 3GB file in C:\Users\myusername\AppData\Local\Temp\MSSDMC
that has a long encoded name that I can't figure out what it is.

I f'ing Googled MSSDMC and there were 0 results. Zero. WTF?

Anyone got any info on this? I'm deleting it and seeing if it comes back.

Attached Thumbnails
What is this 3GB file?  MSSDMC?-mssdmc.jpg  
My System SpecsSystem Spec
29 Jan 2010   #2

Windows 7 Professional x64


I wonder if that is a virus. It is suspiciously close to the file MSSDMN.

While that is not necessarily correct, running a virus scan is never a bad idea.

I recommend Malwarebytes if you suspect your computer is infected.
My System SpecsSystem Spec
29 Jan 2010   #3

Vista Ult64, Win7600

Delete it, it is in the Temp folder.
My System SpecsSystem Spec

29 Jan 2010   #4

Windows 7 Ultimate 32 and 64 bit

@Johnathan_King - I don't suspect a virus, my system has had AV scans daily since it's inception. Also confirmed by scanning the files directly.

@jfar - probably what I'll do.

Interestingly I did a google search on the file name (hash) and it came back as a SHA256 for the ISO of Windows 7 on some French blog. Crazy! 63C02E9F0B91061203CA67D71456EA0F8A8C5C90134439C707DE32090251391E - Google Search=

I'm thinking it's like a temporary file for Windows setup? I was just curious if anyone else had this file in their temp directory.
My System SpecsSystem Spec
30 Jan 2010   #5

Windows Seven Ultimate

After you deleted it manually, run disk cleanup (type in start menu search) to remove any other temp files.
My System SpecsSystem Spec

 What is this 3GB file? MSSDMC?

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