The step to set file associations to 7-Zip in Windows 7 and Windows Vista?
Step 1: In administrator mode, run the 7 Zip
Step 2: Right-click the icon of 7-Zip File Manager,
Step 3: Click-> Run as administrator.
Step 4: Change the file associations and some other options.
Why the archives created by 7 Zip new version is larger than the old version of 7 Zip?
Old version of 7-Zip (before 15.06 version )
- File sorting “by type” (“by extension”).
The new version of 7-Zip supports two sorting orders:
- sorting by name – default order.
- sorting by type,
- Case 1: ‘qs’ is specified in the Parameters field in “Add to archive” window,
- Case 2: mqs switch for the command-line version
The compression ratio is different for different sorting methods. For example, for similar files in separate folders. The sorting is “by type” provides a better compression ratio in a few cases.
Increase the compression ratio with the following methods:
- The increase dictionary siz is helpful when ‘qs’ not used.
- Specify ‘qs’ in the Parameters field
- Else use -mqs switch-> command-line version
use ‘qs’ mode for the better compression in a small dictionary
Why can’t 7-Zip open some ZIP archives?
If you see the message “Can not open file ’a.7z’ as archive”, which implies that 7-Zip can’t open some header from the start or the end of the archive. In such cases, open the file in a hex editor and Start Header and End Header.
Some ZIP archives were encoded with methods unsupported by 7-Zip, for example, WinZip.
Why can’t 7-Zip open some RAR archives?
7-Zip 9.20 doesn’t support RAR5 archives. But the latest versions of 7-Zip supports RAR5 archives.
Why doesn’t -r switch work as expected?
7-Zip can compress subfolders without -r switch.
7z.exe a c:\a.7z “C:\Program Files.”
compresses “C:\Program Files” completely, including all subfolders.
7z.exe a -r c:\a.7z “C:\Program Files”
search and compresses the -> “Program Files” in all subfolders of C:\
If you want to compress only files with some extension, user-r switch:
7z a -r c:\a.zip c:\dir\*.txt
compresses all *.txt files from folder c:\dir\ with its subfolders.
How to store the full path of a file in an archive?
Change the current folder to folder which is common for all files that you want to compress and use the relative paths:
cd /D C:\dir1\
7z.exe a c:\a.7z file1.txt dir2\file2.txt
Why 7-Zip unable to use big dictionary in 32-bit Windows?
For one application 32-bit window allocates only 2 GB of Virtual space, and the DLL file can fragment the block of 2 GB. Hence 7-Zip can’t assign one contiguous block of virtual space, but no such limitations exist with 64-bit Windows.
How to install 7-Zip in silent mode?
For exe installer:
· Use the “/S” ( for silent installation)
· the /D=”C:\Program Files\7-Zip
Note: All are case-sensitive.
For msi installer: Use the -> /q INSTALLDIR=”C:\Program Files\7-Zip” parameters.