Can I have Mac Retrospect Desktop v14 and v16 both installed at the same time?

[like2backup]

I'd love to do this until I test my migration to R16!

[DavidHertzberg]

like2backup,

You can't have both versions installed on the same boot drive, but you can have them installed on different boot drives on the same Mac.  You just have to use System Preferences -> Startup Disk to pre-designate which drive you are going to boot from after a Restart.  If your "backup server" is  a "cheesegrater" Mac Pro that is already booting under macOS 10.14 Mojave, that's the only way you'll be able to switch between boot disks—because Nvidia video cards won't work under Mojave and the hold-down-the Option-key-at-startup facility doesn't work for AMD video cards under Mojave.

In my inherited Mac Pro (5,1) I currently have an SSD that runs Retrospect Mac 15.6.1.105, and a HDD that runs Retrospect Mac 14.6.  I keep my only set of catalog files in Library -> Application  Support -> Retrospect -> Catalogs on the HDD, and back them up with a separate Favorite Folder covering only that Catalogs folder—because I no longer back up the rest of that HDD.

P.S.: The key fact here is that the format of Media Sets didn't change from Retrospect 14 to Retrospect 15, and—according to the cumulative Release Notes—didn't change from Retrospect 15 to Retrospect 16.  The exception is the new Storage Groups feature, but if you're going to use one Storage Group for more than one backup script simultaneously it can only be for Proactive scripts—and those backups won't do data deduplication between the multiple disk or cloud Media Sets for which a Storage Group is merely a somewhat-transparent container.

Edited March 7, 2019 by DavidHertzberg
Added P.S. about prohibition on using Retrospect 16's Storage Group feature; in 2nd prgf., the inner folder is named Catalogs

[like2backup]

9 hours ago, DavidHertzberg said:

like2backup,

You can't have both versions installed on the same boot drive, but you can have them installed on different boot drives on the same Mac.  You just have to use System Preferences -> Startup Disk to pre-designate which drive you are going to boot from after a Restart. ...

P.S.: The key fact here is that the format of Media Sets didn't change from Retrospect 14 to Retrospect 15, and—according to the cumulative Release Notes—didn't change from Retrospect 15 to Retrospect 16.  ...

Thanks for the information, David.  I have a pretty simple setup, backing up my own iMac and occasionally my second laptop or my wife's MacBook Pro.  Knowing that the media set format is the same, is a great relief, but what about the catalog files?  Will they need to be converted or rebuilt?

[DavidHertzberg]

On 3/7/2019 at 11:23 AM, like2backup said:

Thanks for the information, David.  I have a pretty simple setup, backing up my own iMac and occasionally my second laptop or my wife's MacBook Pro.  Knowing that the media set format is the same, is a great relief, but what about the catalog files?  Will they need to be converted or rebuilt?

The short answer to your question appears to be: No, they won't have to be converted or rebuilt.  (Please be aware that I have never done a paid minute of work for Retrospect Inc. or its predecessor companies.)

However you raise an interesting point, which I should have noticed had I not been writing the P.S. you quote above in the early hours of the morning.  Like a mathematical set, a Media Set is a concept—one that was (under the name of Backup Set, which is still used in Retrospect Windows) thought up by someone at Dantz Development Corp. more than 30 years ago—which exists only in the GUI.  The physical embodiment of a Media Set is a Catalog File plus Member folders.  A Storage Group, a concept new with Retrospect 16, is a set of Media Sets that the GUI treats for most purposes as if it were a single Media Set.  The physical embodiment of a Storage Group is a pseudo-folder—by default within the  Library -> Application  Support -> Retrospect -> Catalogs folder—that encloses several Catalog Files and can somehow be made to generate more Catalog Files.  The format of an individual Catalog File, as well as the format of a Media Set's Member folders and their contained backup files, has apparently not changed with Retrospect 16.

The Retrospect Inc. engineer who wrote this Knowledge Base article was evidently trying to get this idea across when he/she wrote the "Under the Hood" and "Data Deduplication" sections at the bottom of the article.  However IMHO he/she didn't do a good-enough job.  One reason is that the engineer was trying to explain the Retrospect Windows GUI embodiment of Storage Groups, which (because the Roxio engineers chickened out on switching to the Retrospect Mac GUI and terminology when Retrospect Windows 8 was developed around 2010) is necessarily less transparent than the Retrospect Mac 16 embodiment.  The other reason is that he/she was probably sleep-deprived when writing the article just before the release of the new version.