When I got up on Wednesday morning, I had no email in my main Gmail inbox. None. Nada. Zilch. Goose egg.

I am subscribed to about 20 newsletters on a wide variety of topics. I’m on at least a hundred mailing lists. I regularly correspond with 20-30 people — since I’m currently seeking a contract position (C++/Linux/embedded), a lot of the most recent are recruiters. I generally do triage on my inbox shortly after I get up in the morning, and pick out 10-12 relatively important emails from the 35-50 in the inbox. I generally get between 200 and 300 non-spam emails a day, most of which get automatically filtered into labels which I occasionally data-mine, but rarely read.

But Wednesday morning, nothing was showing up even in my newsletter folders. At least not on my Android tablet — so I checked my Android phone. Hmmm… nothing there, either. Then I went to my PC. Nothing there on my main account.

Since something was obviously seriously broken, I started doing what I do best — debugging.

There were several clues.

• There were about a dozen trash entries in my calendar on that account, scattered over the past 3 days.
• None of my other Gmail accounts appeared to be acting abnormally.
• Messages were showing up in “all mail” — including a boatload of spam.
• Thunderbird was picking up an unusual volume of forwarded email, nearly 1000 messages overnight.
• Gmail was very sluggish.

On Tuesday, I had installed some SEO add-ons to FireFox, so the first thing I did was to un-install them. After all, the last thing you changed is always the most likely suspect. No joy. Next, since it was obvious that my filters weren’t working, I started examining all of them, changing some of the settings to at least make it easier to find emails from recruiters, which is kind of important to me right now. I have several hundred filters, so that took a while. Then I found the source of at least one of the problems (my experience as a programmer is that there is almost always more than one problem): Down at the very bottom of the filters list, there was one that had no selection criteria at all, with a “bypass the inbox” and “never send to spam” which explained the behavior I was seeing. There is no way that I know of to deliberately create a filter without search criteria in Gmail, so at least one mystery remains. I was able to delete the filter. While I was at it, I unsubscribed to a technical newsletter that I don’t use any more, and deleted all of the back issues.

Within a few minutes, my phone announced the arrival of a new message, so I had fixed at least one major problem.

Thinking back on events earlier in the week, I recalled one that might possibly explain part of how that happened. I remember pulling my tablet out of its carrier and finding it in a strange state. It was on, warm to the touch, down to about 12%  battery, showing a message in my Gmail account, and unresponsive until I reset it. That lock-up occurred again later that day, so I started powering down the tablet whenever I put it away. That makes things less convenient, because now it takes a minute to access my tablet, but until I figure out what’s turning it on in my briefcase, I’ll just have to put up with that. It’s possible that the tablet could have spewed the trash into my calendar and created the defective filter.

Although the worst of the problems is currently fixed, I’m still observing some strangeness in my Gmail account. One really annoying thing is that I will see a message in my inbox on the PC, but I can’t read it. Usually that will self-correct in about 10 minutes. I’m also seeing a message count on my Android phone, but when I open the app, there are no messages available. Sometimes, I can switch to “all mail” to see what came in.

I routinely use Thunderbird to back up all of my Gmail accounts (including my wife’s account), so I’m reasonably sure I haven’t lost anything (at least I hope I haven’t) prior to sometime on Tuesday. And, when I see the glitch where I see a message count, but no message, I can pick it up with Thunderbird. However, I only have Thunderbird on one machine, which is kind of limiting.

Despite my efforts to reduce my dependence on Google, a failure of this type is still a major inconvenience, so I plan to further reduce that dependence by setting up a pop account on this domain, and transitioning all of the important stuff here, so that I can have a bit more control over it. And since I’m still having Gmail problems, I’m still searching for clues.

Edit Feb 4, 2013: My wife was having a problem similar to the one I was having with new emails not showing in the inbox, but only on her phone. Turns out that a recent Gmail app for Android update turned off the automatic sync for the inbox. Since I fixed that, Gmail is working more-or-less normally for both of us. Also, looking back on the events of the past week, I think I have isolated the most likely candidate for the cause of the initial strangeness. Now that I turn my Android table completely off every time I put it away, it doesn’t have the glitchy behavior that I observed last week. I’m guessing that the latest Gmail app for Android started this mess, but I may never be sure of that.