The bug
When using the "backup" option for a world, I get "backup failed" if the world is a symbolic link in the saves/ folder. This is on win7x64.
How to reproduce
I had a 1.16 snapshot world last played with 20w22a
I upgrade to 1.16 pre1
I select my 1.16 world in the game with the 'edit' option so I can make a backup
I click 'backup' and I get the 'backup failed' error message
Linked issues
is duplicated by 1
Comments 7
I followed your instructions and have the log url: https://paste.ubuntu.com/p/pRf6CybvdH/
Here are the exact steps I used to create the problem:
Minecraft launcher:
Using an installation with '20w22a' active, create a new world
and call it '20w22a'
[All default options]
Play that world briefly for a minute or two
[F3 shows 20w22a (20w22a/vanilla/snapshot)]
Quit/save the game & launcher
Using windows explorer, move saves/20w22a to E:/worlds
Result is E:/worlds/20w22a
In windows using cmd.exe "as administrator":
c:
cd \users\imdave\appdata\roaming\.minecraft\saves
mklink /d 20w22a e:\worlds\20w22a\
Symbolic link created for 20w22a <<===>> e:\worlds\20w22a\
Start minecraft launcher
In Minecraft launcher:
Click on installations
select installation '20w22a'
click "..." and then "edit"
change version to "snapshot 1.16-pre1"
click "save"
From "Play", with installation "20w22a" active, click "Play"
After the game starts, choose single player, select world "20w22a"
I see the warning "Don't forget to backup this world before you load it in this snapshot"
I click "edit"
I click "make backup"
I get warning/error message in top right corner: "! Backup failed, C:Users\imdave\Appdata\.. " (remainder truncated)
I then quit/saved the game & launcher and have provided you with the launcher.log
Note: I also tried with 1.16pre2 and got the same results.
It appears to me that when you try to create the ZIP backup file, you are not followng the symlink – the ZIP contains exactly one file of zero length and is the name of the world.
Plausible due to similar (if not even the same) issue in MC-174913.
+ since worlds are by default created on ones C: drive – along with just about everything – it is very useful to be able to move the very large minecraft worlds to another drive having more available space
+ other archive programs such as 7z have no problem "doing the right thing' – an archive is created which contains the files which are referenced by the symbolic link
+ the minecraft launcher warns and encourages one to make a backup but then fails
+ after failing to make the backup, the launcher >with no further warning< will launch the game which effectively updates the world to the newer version of minecraft
I thought I'd add an additional comment: the real bug here is that, although the launcher knows that the backup failed (an error message is issued after all), the launcher still marks the world as though the backup succeeded. This means that if one dutifully follows the instructions to make a backup but, for whatever reason, misses the error message and clicks Play then the launcher no longer issues the warning and launches the game. This permanently destroys the prior version of the world and the user has no valid backup.
The launcher should not reset the warning unless a backup is successfully made.
We do not have enough information to find the cause of this issue.
Please add the launcher log using these instructions to this ticket - please copy the log after the error has occurred.
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