Remember when you were fresh out of college and you started your first IT job? Remember the mistakes you made that not only cost you time but maybe, in some cases, cost you respect? Those newbie mistakes can be easily avoided with just a bit of care, caution, and knowledge. Most important is simply knowing that they happen. Knowing is, after all, half the battle.

With that in mind, I thought I’d share some of the newbie mistakes I’ve either committed or witnessed over the years, so you can file them away under “Remember not to do this.” I won’t tell you which mistakes I’ve made and which I’ve witnessed, but I’m fairly certain you’ll find at least one on this list that you’ve either committed or seen.

1: Where’s the backup?

You’re faced with a situation that requires the reinstallation of an operating system and you plow into that reinstall before taking a mental inventory of what has been done. You have account information, you have passwords, you have time. Unfortunately, as soon as you start the reinstallation, you realize you forgot one critical piece of the puzzle — you failed to back up the user’s data. Sure it’s fine if that data is housed on a server, but not all networks are created equal and some user data resides alone on their client hard drive. If you forgot to back up that data, and you’ve reinstalled the OS, you’re out of luck. At this point, it’s time to start sucking it up and taking the punches you will inevitably receive.

2: What’s the password?

One of the most commonly forgotten pieces is the password. That’s okay if you’re on an Active Directory domain and you know the domain administrator password. In that case, just reset the forgotten password and move on. But when you forget the domain administrator password, guess what? You’ve got a long, hard road to travel. The domain admin account must be remembered — or documented. This is a mistake that can be made by anyone, not just a newbie. But don’t put yourself into this position. You will wind up frustrating everyone involved (and possibly costing the client a lot of time and money).

3: What’s your account information?

If you’re dealing with a client and you have to blow away his or her Outlook profile (for whatever reason), make sure you have the account information before you delete the problematic profile. If the profile is bad and won’t let you open Outlook, get the profile information from the Mail tool in the Control Panel. Along these same lines, make sure end users know their password, especially if you don’t control the mail server.

4: You forgot to bring what?

You’ve driven to your client, only to realize you forget to bring along a crucial item to the appointment. At that point, it’s time to turn around, grab the forgotten hardware, and hope you can make it back in time to finish the job. I’ve even seen engineers leaving for appointments without the computer they were supposed to deploy. Do whatever you can to avoid this. It makes you look really bad and costs you precious time (but shouldn’t cost the client money).

5: Was that your production server?

Before you do something you’re unsure of, find out if the machine you’re about to work on is a production server. If so, do you really mean to begin the process you’re about to undertake? Or should you be doing it on a non-production machine first? This could have serious, long-term ramifications (of the type that causes you to lose clients — and income).

6: You deleted what?

You’ve seen the look on your clients’ or end users’ faces – that look they get when they realize you deleted an irreplaceable file that had no backup. That look will haunt you. Before you delete anything that might be remotely of worth, verify it with the end user. If they give you the green light, trash that baby. Otherwise, keep it. Many times, I’ll create a folder and dump what I think could be deleted into it for the user to pick through at a later time.

7: How could you forget to reboot?

You did updates on either a client or server machine, you thought you were done, and you walked away without a reboot. Unless you’re working on a Linux box, most likely that machine will need a reboot –especially after a major update. Granted, most times you will be notified the reboot must happen. But sometimes we dismiss those warnings to finish something else and forget they were ever there. Big mistake. If you don’t reboot, all those changes won’t take effect.

8: Why did you reboot without warning?

In the same vein, when you reboot a server, you’d better make sure you warn all users. You never know if someone is in the middle of some critical work. Or what if users are all connected to QuickBooks and you reboot? That could spell damage to a data file. Always, always, always get permission to reboot before you do. And verify that everyone has disconnected from whatever they were doing on the server.

9: How many DHCP servers did you set up?

That’s right — more than once, I’ve seen engineers setting up a router, complete with DHCP server, on a network where a server was already charged with handing out DHCP addresses. We all know what happens to a network when this occurs. Chaos. If you’re about to roll out a new router on an already established network, make sure you know the purpose of that router. Is it supposed to just serve as a wireless access point? Is it supposed to take over DHCP? Know the details before you cross those streams.

10: Why didn’t you register that software?

One of my least favorite tasks is registering and validating a QuickBooks installation. After spending the time to get the software installed and to get all the clients reading the data file, the last thing I want to do is have to call Intuit and get the validation code. But I do it…without fail. Unfortunately, this (and similar issues of registering software) falls by the wayside all too often. What happens when this occurs? The client winds up having to handle the registration. Or they neglect to do it and 30 (or so) days after you did the installation, you get a call from the client asking for your help registering said product. When you have to make a trip out to register software, this is (or should be) on your dime.

Other mistakes?

We all make mistakes — some worse than others. But certain mistakes can and should be avoided, not only to keep from looking like a noob, but to retain both respect and clients. Although the mistakes on this list might look like things you would never do, think back on your early years and give yourself an honest evaluation. Did you make any of those mistakes? Share your experiences — and cautionary tales — with fellow TechRepublic members.