CrashPlan has banned a bunch of file formats from its online backup system aimed at small businesses.

The company (tagline: Automatic Data Loss Protection for Your Small Business) sent out emails on Friday with the new list of forbidden formats.

For users of CrashPlan for Small Business, these include application directories, VM image files and some backup file formats.

Some of the new exclusions:

Applications: /Users/<username>/Applications, /Applications/, /Program Files/, /Program Files (x86)/

/Users/<username>/Applications, /Applications/, /Program Files/, /Program Files (x86)/ VM image files: .hdd, .hds, .pvm, .pvs, .vdi, .vfd, .vhd, .vmc, .vmdk, .vmem, .vmsd, .vmsn, .vmss, .vmtm, .vmwarevm, .vmx, .vmxf, .vsv, .nvram, .vud, .xva

.hdd, .hds, .pvm, .pvs, .vdi, .vfd, .vhd, .vmc, .vmdk, .vmem, .vmsd, .vmsn, .vmss, .vmtm, .vmwarevm, .vmx, .vmxf, .vsv, .nvram, .vud, .xva Backup files: .bck, .bkf

.bck, .bkf Other files: .tmp, .part, .rbf, .tib, .sparseimage

The full list of excluded file types is here.

Although there seems to be customer support for some of the changes, the company was criticised for failing to communicate the list in a timely manner.

Users on the relevant subreddit claimed CrashPlan had deleted files in the those formats with no warning.

One raged: "I used CrashPlan because it had a decent UI and it allowed you to upload from Program Files, where a lot of applications store important data (Like FL Studio save files, audio files, presets, etc). First they decided to dumb down their UI to the incredibly ugly UI it has now, which wasn't necessarily a dealbreaker but was annoying as hell. Now they force exclusions of critical areas and delete backups with no warning? What a fucking joke. Just cancelled my subscription and finding an alternative now."

Another blasted: "Everything I've backed up for my 15 clients for the last 2 years is gone. Not only did it just plain stop backing up current data, it also deleted my entire history: I can't restore anything either.

"No notifications, no alerts, never got an email, no warnings beforehand, no alerts that all by backups sets were now 0 bytes in size. And I can't change it.

"This is the company that has on its home page 'Automatic Data Loss Protection for Your Small Business' and 'Never worry about losing business-critical data again'. They deleted my business critical data. On purpose."

But that seems pretty generous compared to how many consumer cloud services treat their punters – we're looking at you Flickr...

A spokeswoman told The Register: "CrashPlan for Small Business was designed to back up and restore business files (e.g. documents, spreadsheets, presentations etc.). We have recommended for some time against using CrashPlan to back up operating systems and applications that run continually because it was never intended for that use and, as a result, may not function properly. This recommendation recently became a policy, and we updated the default list of files excluded from backups. The primary goal of CrashPlan remains the same – to ensure that customers' business files are protected."

Back in 2017, CrashPlan gave customers 14 months to get off its service aimed at home users. The platform is run by Code42, which provides services for companies with more than 199 staff. ®