When a mobile wallet fails, it doesn't go away. Companies can upgrade dormant apps and remove their functionality, but the apps stay on users' phones, each one a headstone in a growing digital graveyard.

The problem gets worse with wallets tied to a specific handset or carrier. The product page for Softcard, which shut down at the end of March, has several reviews from people who would be glad to see it gone, if only they could delete the app from their phones. Softcard was operated by AT&T, Verizon Wireless and T-Mobile, and in many cases the app came preinstalled on the handsets sold by those carriers.

It's the mobile wallet version of Songs of Innocence, the U2 album that Apple forced upon all iPhone users last year without a clear way to get rid of it.

"This app came with my phone and I am not allowed to delete [it] ... even though the app itself says it is defunct," wrote one Softcard reviewer identified as Bethany Hagen, who also wondered why the app was still getting updates pushed out after its sunset date.

"Bloat ware," wrote another user, Dennis Peace. Both Hagen and Peace gave Softcard one star, out of a possible five, in their reviews.

Softcard isn't the only app to face this problem, but perhaps it is the hardest to remove. Lifelock briefly stopped downloads of its app following a self-diagnosed security concern, and Square Wallet no doubt remains on some phones despite Square shutting off the service a year ago. Even Starbucks, which is still an active innovator in mobile payments, used to have a separate Starbucks Card app that it stopped supporting after moving the payment functionality to the company's main app.

Now, with Softcard's capabilities gone (even if its corpse remains buried in the code of many consumers' handsets), Google Wallet will come pre-installed on phones sold by the Softcard carriers. If Google Wallet doesn't succeed and Google doesn't provide a way to remove it, it may linger on consumers' phones as a reminder of the failure of yet another mobile wallet. Samsung faces the same peril with its yet-to-be-released Samsung Pay.

This is bad news for these companies if they want a second chance. Striking out with a particular product doesn't remove any vendor from the game. For example, Google has made several revisions to Google Wallet since the app launched, including merging the product with its earlier (and somewhat troubled) Google Checkout. And Square went through several different iterations of Square Wallet during the product's life.

In many cases, new wallet apps simply overwrite the old one (such as LifeLock Wallet, which used to be Lemon), but it still sends a bad message to have dead apps littering the user's screen while the vendor works on its next project.

Verizon, on its own website, provides instructions for removing the Softcard app, though the aforementioned consumer complaints suggest this process does not work for all carriers and phones, or at least that the process is not obvious to many consumers.

Otherwise, Softcard's end-of-life process has been graceful. The app suggests users download Google Wallet as a replacement (though it can't automatically transfer user accounts to Google Wallet), and even includes a link to Google Wallet on the Google Play app store. The company also sent a handful of push notifications reminding users of the change, so they are not caught off-guard at the point of sale.

But for many consumers, the app will linger until it's time to buy a new phone. And when they do, they'll likely pay for that phone with a plain old plastic card.

Daniel Wolfe is Editor-in-Chief of PaymentsSource.