I am experiencing exactly the same issue. I updated my Roon server to version 2.65 build 1653 and have since not been able to get past the “there was an issue loading your library” error message. I have tried all of the remedies that are usually recommended in the forum in vain. I also executed clean installations of the Roon server and attempted restoration of my database on a ROCK mini pc, an iMac, and a Ubuntu Linux computer with no success. I also checked my MacOS and Linux installs to make sure that they also met the new minimum requirements of Roon for server version 2.65 build 1653 and beyond. The Roon server instance on the Linux computer was my original decommissioned setup and actually worked perfectly for a few minutes after startup because it was still on Roon server version 2.64 before it automatically updated to version 2.65. I unfortunately had not realized that version 2.65 might be buggy before that automatic update happened, I would have otherwise changed the setting to “Ask before installing any update”. Each setup failed every time I tried to restore my library from good backups that I have successfully used before to recover from a corrupted database. The backups are located on two separate computers and I keep a sets of at least ten backups that are created every 3 days on each target. I shudder at the thought of having to rebuild playlists that I meticulously curated over many years of using Roon. I hope that you can duplicate and fix this bug before the next server release so that affected users can successfully restore their libraries from backups that worked fine in server versions <= 2.64. Thank you.
I’ve run into this issue too, immediately after upgrading to 2.65. I have the same exception in the logs (Warn: CompressedPath exception: System.FormatException: The input is not a valid hex string as it contains a non-hex character.)
Also worth mentioning: the error message is partly cut off in the remote app running on Android. It looks like this:
A week after the unpleasant realization that my carefully maintained Roon backups could no longer be restored after updating to version 2.65, I’ve come to a new understanding of the broader challenge that issues like this represent for software developers in general—and specifically for the team at Roon.
Given the nature of the problem, I decided to simply start from scratch with a clean installation, still based on my music library of roughly 5,000 albums, of which about 700 were not immediately identified by Roon.
To my surprise, the task turned out to be more engaging and easier to complete than I had feared. It is also refreshing to gain a completely new overview of one’s music collection. According to ChatGPT, my old backups—containing accumulated edits made over a period of 8 years—would in any case likely be cumbersome to work with going forward, including an increased risk of eventually “hitting the wall” again at some point in the future.
My recommendation is therefore to use the waiting time until the Roon developers hopefully find a solution to begin rebuilding the database based on version 2.65, which, incidentally, runs very smoothly in my setup. My guess is that many users may choose to keep the new database even once the current issue is resolved.
Don’t get me wrong: if you have a much larger music library than mine, or truly irreplaceable playlists, your situation is of course quite different from mine, and I sincerely hope a solution will be found in the near future.
Keep up the good spirits!
Michael Madsen
So we are a week into this, is their any update from Roon? I have realised that my setup, which uses an Oppo UDP-203 in my main setup and several S1 Sonos devices that now only work with Roon cannot play anything I don’t have a physical copy of, which I am getting tired of very quickly.
I think my takeaway from this experience is to keep copies of every new Rooninsteller exe, particularly the “big” “upgrades”, as you never know when when you are going to lose the ability to play your whole collection (sadly an all too common occurrence in the “IoT” age), or how long that ability is going to be gone for, and Roon sure as hell aren’t going to offer that option for you to get up and running in the short term.
If I sound annoyed, that is because I am.
There is no point in keeping old versions of Roonserver.exe install files because they always automatically updates the new install to the latest version of Roon.
Michael
Stop it from finding updates 
Hi Michael,
Firstly, I apologise as I think my last message was a direct reply to yours, however that was done in error by me and should have just been a general comment. I am used to the workings of a different forum! 
My version of Roon doesn’t (or I should say, didn’t) ever update automatically and asks separately for the server and any controllers I have. That being said, even if I manually updated (which I did) and the processed failed (which it did, immediately and presumably with no change to the database), I can uninstall and reinstall the old version to get the system working again. The uninstall process gives you the option to remove the database or not, and I have used this several times when Roon has had corruption issues.
The OP has already mentioned that installing an older version has allowed him to import backups as well (which would obviously still be in the old format). I have confirmed this, but as the most recent downloaded version I have of Roon is from last year, the server and database versions don’t match so only some functionality was available.
The evidence suggests that a copy of version 2.64 would probably work on my current database and definitely work to get my last backup up and running, which was only from a few weeks ago.
So yes, I will be keeping previous versions for the foreseeable future as, from experience, Roon staff seem to have little interest in fixing issues that affect a minority of people, but a high probability of those issues occurring.
Jason - Quality Assurance Analyst by trade.
Does 2.66 fix this issue in importing database?
No, unfortunately not! Same issue with the older backups…
I had to re-install Roon and use my recent backup I made just after updating to 2.66 - and it worked 
Do you mean a backup made on 2.64 yesterday may work if i install 2.66 and restore it (1 day old but with version 2.64)? thx
I tried to restore the older problematic backups after updating to the latest early access version of 2.66 called 1657 and the backup issue is still not solved. Sorry if I made this unclear.
Any update on the topic please? @connor
Hey, @Fulvio_Salanitro
Thank you for the continued patience, and for checking back in on this. Our development team is still investigating possible causes and potential solutions, and we’ll be in touch once we have more to share. 
Hi @Fulvio_Salanitro and others experiencing this issue,
It appears that the database backup we had to test further is no longer available, and our development team is hoping to grab a fresh copy of an issue backup for additional testing.
If you could, please:
- Zip up a copy of one of your issue backups
- Submit the .zip file to our private uploader below:
Thank you!
Wow, that really doesn’t sound like your “development team (was) still investigating possible causes” at all.
Meanwhile, I have followed Michael’s route and done a fresh install of Roon. Here are a few things I have noticed:
- Roon has been unable to identify around 10% of my library. I noticed this number was even higher for Michael, so I guess I am lucky? I would consider this somewhat unsatisfactory though.
- My estimate of a week for the system to handle volume levels etc. seems to be about right. Bear in mind, I can really do nothing with the system until that is finished and it is backed up. Although…
- I have to question whether backing up is even worth it when it appears just as likely that the back-up won’t work in future builds anyway.
- To even “test” that any updates are fixing the problem is at least an hour process to backup the current, install the update, find out it doesn’t work, completely reinstall the server and restore the latest backup with fingers crossed. No doubt the Roon devs will have us do that multiple times.
- I have noticed this error that I had is no longer an issue. At the time I was almost 100% sure this was to do with the database, as in the meantime I had completely rebuilt the computer and reinstalled Roon from scratch and the problem persisted with the backup I restored. I am almost sure the current issue is caused by the same database error, call it Tester’s intuition. Note this issue was sitting around for a month with multiple, I will kindly say “unhelpful” suggestions to fix it, then it was closed only an hour or so after my last comment was made with no resolution whatsoever. I would be interested if anyone with database issues now had the same behaviour I did back then (which was Roon constantly showing it was scanning for new tracks).
Considering the last problem was never fixed and the similarly vague answers we are receiving here, I honestly don’t hold much hope for this one, which is disappointing to say the least. I had multiple playlists, some that I spent hour curating for specific events down to the second, with these being impossible to recreate.
I will say that for the several years I have used Roon, it seems to have gotten worse rather than better, especially with artist information which just seems to be sourced from Wikipedia now. I should just have a Wikipedia window open instead! The upshot of this latest failure is that rather than just not talking about Roon, I would actively discourage people from using it. There is too much time spent trying to fix un and mismatched items, it relies way too much on being connected to the internet (for basic search operations!) and the risk that you can lose your carefully curated libraries is just too great.