Deleting files from 7z format archives

dtjacobs

I recently started to recompress some of my folder backups from Zip to 7z to save some space.

I never noticed this before but I made a copy of on of these backups and went to remove extraneous files from the copy. But under this 7z format, the Delete option was greyed out. Under the Zip format, (the same archive of files) allowed me to delete the files I wanted.

Why am I not able to delete files from a 7z format archive?

Jr heuwing

7z archives are solid just like CAB files. It is not possible to delete file from a solid archive.

The only way is to extract the arvhive, delete the files and then recompress the archive.

Brian Gregory

@Jr:

7z archives are solid just like CAB files. It is not possible to delete file from a solid archive.

The only way is to extract the archive, delete the files and then re compress the archive.

Yes that’s probably what’s happening in this case. It’s worth nothing though that 7z archives are optionally solid – you can choose solid or not solid when you create a 7z archive. Obviously solid usually gives better compression ratio with the trade off that you can’t delete files from the archive.

mwb1100

I thought that the miscellaneous option “Enable transparent updating for 7-ZIP for files smaller than…” would allow you to delete files within a solid 7z archive (in this case PowerArchiver would extract/delete/recompress for you behind the scenes).

I have this option checked and the Add operation is enabled, but the Delete operation is not. Should it be?

RJWaring

I have tried selection the option to have the 7z Solid and not Solid on many occations when using large spreadsheets and it still does not allow me to select delete within the archive.

Would this possibly be a bug I wonder?

davidsplash

There is a simple way to resolve this and that is to allow updating i.e un 7z and re 7zing up and if it encounters not enough space for the operation a warning message comes up.

spwolf

@Sir:

I have tried selection the option to have the 7z Solid and not Solid on many occations when using large spreadsheets and it still does not allow me to select delete within the archive.

Would this possibly be a bug I wonder?

for 2008 we will add “updating” to transparent support…

We cant properly detect if archive is sold it or not, so we cant have delete/add to non-solid archives, WITHOUT transparent option…

RJWaring

Gotcha! ;) cheers Spwolf