Ryan, With the release of vSphere 5 (the newest version), ESX no longer exists and ESXi is the main hypervisor going forward. The difference between the two is that ESX existed long before ESXi and had something called a service console (later versions based on Red Hat Enterprise Linux) that it used for management and other things while ESXi does not have the service console and allows for complete remote management. Since vSphere 4, there were no major feature differences between the two and as of vSphere 5, ESX is no longer updated to keep up with new features. In terms of feature levels, there are no different versions of ESXi to install as it's all controlled by the license key you apply. When you install ESXi, you get a 60 day evaluation of the full featured product at the "Enterprise Plus" license level. To take advantage of all of those features, you need vCenter (or Virtual Center as some people still call it) which comes in two versions; a Windows application (requiring either commonly SQL Server or an Oracle db) or a Linux-based virtual appliance. The virtual appliance has a web client for management of vCenter, the ESXi hosts, and virtual machines, or you can use the "vSphere Client" which is a Windows application, for the same purpose. The vSphere Client is required if you're going to configure/manage a single ESXi host. The vSphere Client can only connect to one ESXi host at a time, however you can open up as many instances of the client as you want. In the bottom of right corner of the client when it's connected to an ESXi host or vCenter server, it will say the days remaining in the evaluation license. If you do not want or need the features the paid versions of ESXi and vCenter give you, you can go to the web site linked by Erik Anderson below to get a free license key to allow you to run ESXi legally. All you would need to do is enter the key into the licensing portion of the vSphere Client when connected to an ESXi host and it will apply immediately. Using a keygen to get a license key and piracy in general, isn't recommended. I recommend reinstalling ESXi on that host from an ISO you get from the VMware web site as you can't always tell how that ISO may have been altered. If you are interested in purchasing vSphere and can guess the virtualization needs for the near future, let me know as I could help explain some of the bundles and license levels aimed at small and medium sized organizations that could potentially save some money over going the standard way of purchasing the products. If your needs are very basic, I'd recommend VMware Workstation over the free "vSphere Hypervisor" as that may be more easy to manage for some people. On Mar 23 2012, Ryan Coleman wrote: I guess I need some serious direction here... I don't know how little time is left on my 60-day trial - my normal functioning desktop is not at the moment and I'm stuck at DFW. > Can I downgrade my install somehow? I have 6 VMs built (but 4 running) on this server right now; if it's a headache I'd probably just tell them to buy it so we can expand later. > >I've had a hard time finding a good comparison between ESX and ESXi. > I didn't download the installer or ISO From the site, I used a torrent but did *not* try to keygen or crack it. All I can see from the ISO is that it's called VMVisor5.iso. > >Oh, here we go: ESXI-5.0.0-441354-STANDARD. > >Thanks, >Ryan > >On Mar 21, 2012, at 4:22 PM, Erik Anderson wrote: > >> On Wed, Mar 21, 2012 at 11:52 AM, Ryan Coleman <ryanjcole at me.com> wrote: >>> >>> Where can I find that info? >> >> I guess instead of calling it ESXi now, they're calling it the "VMware >> vSphere Hypervisor": >> >> https://www.vmware.com/tryvmware/index.php?p=free-esxi5&lp=default >> >> VMware's website is notoriously difficult to navigate, but after >> signing into your account there, you should be able to go to the above >> link and find a license key on the "License and Downloads" tab. >> >> -Erik >> _______________________________________________