That explains it. Resizing a monolithic virtual disk basically creates a new .vmdk file because it requires more space for metadata, then copies the data over to the new file, before the old .vmdk file is deleted. Therefore this task requires a lot of temporary disk space (~the size of the current .vmdk file).

Expanding sparse virtual disks (split into multiple .vmdk files) simply adds additional .vmdk files, which doesn't require a lot of disk space and is done within seconds.

What you can do in the current situation is to convert the current virtual disk to a sparse disk using e.g. the vmware-vdiskmanager command line utility. Unless you can free up some more disk space on the host, you may e.g. use an external disk as the target, and - once converted - delete the original .vmdk file, and copy the new .vmdk file from the external disk to the VM's folder. Alternatively, copy the current .vmdk file to an external disk, and use the VM's folder as the conversion target.

André