While trying to upload a theme to one of my wordpress installation I encountered this error.
I tried uploading a zip compressed theme file to my wordpress installation when I received an error saying:
Unpacking the package…
Incompatible Archive. PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature
This error simply means that the package wasn’t extracted. It could be due to several reasons, most obvious one of which is also mentioned that the archive is incompatible. Other reasons could be that the directory or file was not read / writeable or else there was low disk space.
In my case, I confirmed by trying to unzip the file locally on my computer and it failed too, which showed that the file wasn’t in correct format or else it was corrupted!.