In other words, don't hold your breath waiting for a fix that might never come.
The tech went on to explain that Dymo's current printers, the 450 series, do work fine with OS X 10.9.4. The problem was limited to just a "few older models," of which mine was one. Another solution, therefore, would be to buy a new Dymo LabelWriter 450 Twin Turbo. Dymo was prepared to offer a 25 percent discount if I decided to go that route. As it turned out, the same printer was available at Amazon.com for a 50 percent discount ($100). So I declined Dymo's not-so-generous offer and, with some reluctance, ordered the printer from Amazon. I can now confirm that the new printer does work with OS X 10.9.4; I'm printing labels again.
Summing up, Dymo has failed here in several significant respects.
To be fair to Dymo, I understand that a company cannot be expected to support older out-of-production hardware indefinitely. But this hardly seems to be a good example of when to opt out. The update from OS X 10.9.3 to 10.9.4 was a minor one. And, at least superficially, the differences between the Twin Turbo 400 and 450 seem small. It thus seems reasonable to assume that creating a fix would not be a significant drain on Dymo's resources.
If my logic is incorrect here, and the required fix is somehow a big deal, I would at least expect Dymo to offer some explanation on their website. Instead, they have gone the opposite route. Not only does their site make no mention of any of this (at least not as of the time I was dealing with it), but their first line technical support staff has similarly been kept out of the loop. In addition to the misinformed online chat technician, the person behind the @DymoSupport Twitter account at first assured me that my printer should work with 10.9.4. After further discussion with higher-ups, he later acknowledged that "some devices are indeed incompatible." Postings at Apple Support Communities offer similar stories.
Finally, Dymo's suggested solutions of either downgrading the OS X software or overpaying for a new printer, seem unhelpful at best.
The end result is that a functioning printer is headed for the garbage heap (or perhaps to a Windows user) because Dymo is unable or unwilling to fix a software incompatibility. And it cost me $100 to replace a printer that ought to still be usable.
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