For some, an MD5 checksum is the sequence of letters and numbers that shows up next to the file they want to download. For others, it's a handy pointer that the file you've downloaded is the one you were expecting.

A Register reader got in touch after noticing something a bit odd on the Parallels downloads page. The company helpfully provides the MD5 checksum for its Desktop for Mac images, but what got downloaded apparently had an entirely different value. We checked and confirmed that the DMG file linked did not have the same checksum.

This would ordinarily set off alarm bells. After all, there have been a good few examples over the years of poisoned files being sneakily deposited on servers by miscreants seeking their next victim. Could Parallels, purveyors of [1]virtualization tech , have been similarly targeted?

[2]

Thankfully not, although the company has yet to explain how the screw-up happened.

[3]

[4]

By why of explanation, an MD5 checksum is a hexadecimal number computed on a file. A matching checksum means there is a good chance that the files are the same. A different number and, well, it's probably best to steer clear or employ some other method to ensure the download is not about to spray your computer with all manner of nasties.

[5]Desktop 17 for Mac: In a Parallels universe with Windows 11 on M1 silicon

[6]VMware is 'a few months away' from M1 release of Fusion macOS desktop hypervisor

[7]Windows comes to Apple M1 silicon as Parallels delivers native desktop hypervisor

[8]Run Windows on a Chromebook: All the details. Not so fast, home user...

Our reader told us he'd contacted Parallels about the issue and spent some quality time bouncing around technical support. "For OVER A MONTH! [his caps] I've asked for the problem to be escalated," he said.

A [9]glance at the support forums shows the question being asked a week ago, only to be met by stony silence.

At least, that is, until yesterday when a technician posted a terse message that the issue had been fixed and checksum matched the file.

[10]

Far be it from us to say It Woz The Reg Wot Dunnit, but the change occured less than two hours after we got in touch with Parallels to ask for comment. At time of writing, Parallels still has not given us an explanation. We hope that it was down to a delay in a change control procedure rather than an issue being ignored until the media called.

Parallels' product is handy (indeed, we continue to use it to fire up Windows 11 on Arm on an M1 Mac). However, if one publishes a checksum then one should ensure it is correct.

Unless, of course, nobody is bothering to check their downloads before gleefully installing... ®

Get our [11]Tech Resources



[1] https://www.theregister.com/2021/08/10/parallels_17/

[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/virtualization&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YfAsupw@DRgK1kqjndi7MAAAAMU&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/virtualization&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YfAsupw@DRgK1kqjndi7MAAAAMU&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/virtualization&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YfAsupw@DRgK1kqjndi7MAAAAMU&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[5] https://www.theregister.com/2021/08/10/parallels_17/

[6] https://www.theregister.com/2021/04/27/vmware_m1_fusion_release_months_away/

[7] https://www.theregister.com/2021/04/15/windows_on_m1_silicon/

[8] https://www.theregister.com/2020/10/21/run_windows_on_a_chromebook/

[9] https://forum.parallels.com/threads/md5-checksum-incorrect-on-downloaded-dmg-file.356365/

[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/virtualization&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YfAsupw@DRgK1kqjndi7MAAAAMU&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[11] https://whitepapers.theregister.com/