Archive: Extracting Files slow under Windows 8

Extracting Files slow under Windows 8

I have two installers that show the same behavior: (both NSIS 2.46)
The phase where files are being extracted to the installation directory is awfully long under Windows 8 (32/64 bit) compared to previous Windows versions.
e.g. a 620 KB installer unpacking about 1MB of files (total) takes up to 12s to do this before starting the next action/section whereas under Windows 7 (same machine) unpacking is performed in less than a second. (Detailprint for that action is visible together with the GUI appearing after start, on Win8 one can read the "Extracting files...." and wait until the next section does a DetailPrint.

I have already moved from compression lzma /SOLID to lzma only, but no change.
I also tried NSIS 3.0a0 with manifest for Win8 - no change.

The installer where speed is important (10-13s overhead) already has the manifest for Win8 added using MTTool.

Can anybody explain why NSIS under Windows 8 is so much slower extracting files?
Is there solution/workaround?

I've some more information:

- SetCompress off doesn't help neither
- Yes, the installer gets signed with a real VeriSign signature

I'll try to reduce it to an installer just unpacking the files and printing the time consumed after start....

Does the win8 machine have antivirus installed?

Hi Anders,

my answer: NO and YES.

NO - We did not install any AV program
YES - But Windows 8 includes Windows Defender, which does real-time checking of EXE and archive files....

So you solved the mystery!