Older databases won't display in the viewer

[weirdalsuperfan]

I tried opening a database (95GB w/attachments) created with v37.2, but when I open the viewer, it displays the basic UI but no channels or messages or anything.

When I check the console under devtools, it says something like (filename edited for privacy):

Unsafe attempt to load URL file:///...%20downloaded-2026-03-24.html from frame with URL file:///...%20downloaded-2026-03-24.html. 'file:' URLs are treated as unique security origins.

I get this same problem when attempting to open a different old html viewer from 2022.

My database is so big that when I try opening or upgrading a copy of it w/a newer version of DHT, the program stalls after a while and my mouse cursor freezes and I can't get the cursor to unfreeze for some reason unless I restart my computer.

How do I view this old database? What's wrong here? Did browsers change some setting that prevents local file URLs from being read?

(so much for archiving 🙄)

[chylex]

New versions of DHT don't have support for exporting viewers into an HTML file, partly because it just doesn't work with big databases, so I can't provide any support for old HTML viewers. New DHT acts as a web server for the viewer, so there are no issues with browsers locking down the file:// protocol.

I don't know why your computer is freezing when upgrading the database. Could be running out of memory, could be a slow disk, you didn't say your operating system or computer specs. You'll have to monitor system resources while the upgrade is happening and figure out why your computer is struggling. The database system DHT uses is able to handle much bigger databases than 95 GB.

[weirdalsuperfan]

@chylex Thanks for the reply. Does it need to be able to load the whole database into memory to upgrade? I only have 128GB RAM and realistically I think I only have 64GB free at a given time. Is that enough? Should I look for the bug elsewhere besides running out of memory?

And just to be clear, will I have to upgrade the database for it to work? Is there a problem with old (not HTML, just database format) DHT files where they won't load in the viewer even if I use a corresponding old version of DHT?

[chylex]

Does it need to be able to load the whole database into memory to upgrade?

No, unless there's a bug somewhere it should need very little memory. It might try to use a lot of memory to speed things up, but I would expect things to work even with just a few gigs of RAM.

The disk the database is stored on will need as much free space (or realistically, a little more) as the database size, though. There are migration steps that essentially create a temporary copy of the whole database file. Plus you should have a separate backup of the database file before you start the migration.

And just to be clear, will I have to upgrade the database for it to work? Is there a problem with old (not HTML, just database format) DHT files where they won't load in the viewer even if I use a corresponding old version of DHT?

New versions of DHT cannot work with old versions of the database. Old versions will not be able to open new versions of the database. The format in which data is stored has changed significantly over the years.

Then, v42 completely reworked the viewer. Previous versions of the viewer stored every message in an HTML file, which browsers cannot open past a certain size.

Since v42, it's no longer possible to create an HTML file; the viewer can only be opened from the app. Since Discord links expire, having the app open is necessary to view attachments anyway, so I made this trade-off to allow viewing much larger databases - plus it made the viewer much faster and require a lot less browser memory.

Anyway, if browsers used to be able to open HTML file-based viewers in 2022, I assume something changed in the browsers. Maybe a different browser would work, or maybe you could try downloading a portable version of a browser from 2022 at your own risk. Like I said though, viewers work completely differently since v42, so I've not run into this problem with my own archives, and can only help with issues related to the current version of DHT. Worst case scenario, assuming the database file isn't corrupted, it's just a standard SQLite file and you can extract the data out of it.