[SOLVED] Archive checksum error on installer 1.2.6

[agent_kith]

Obviously outside your remit but any suggestions on what is going on with the laptop that is no longer able to set up snakeoil would be appreciated.

Hard to say without more information, as anything is possible.

Things from bad ram, failing ssd/hdd, old flash drives (if you use that to copy files), laptop infected with some unknown viruses, transferring files in ASCII mode and not BINARY mode, modifying the installer file, and probably hundreds (if not thousands) of other possibilities.

Just a single bit change in the installer file will cause that error. And the installer will not continue (this is a good thing) because the installation file is no longer what it's supposed to be.