It don't allow to open a document

[mescobar@…]

What steps will reproduce the problem?

1. Open a file

What is the expected result?

What happens instead?

Please provide any additional information below. Attach a screenshot if possible.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-12-28 22:03:23 +0100 (Mon, 28 Dec 2020)
Revision:17428
Build-Date:2020-12-30 02:30:55
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (17428 en) Linux Ubuntu 20.04.2 LTS
Memory Usage: 180 MB / 2872 MB (63 MB allocated, but free)
Java version: 11.0.8+10-post-Ubuntu-0ubuntu118.04.1, Ubuntu, OpenJDK 64-Bit Server VM
Look and Feel: javax.swing.plaf.metal.MetalLookAndFeel
Screen: :0.0 2726×768 (scaling 1.00×1.00)
Maximum Screen Size: 2726×768
Best cursor sizes: 16×16→16×16, 32×32→32×32
Desktop environment: KDE
Environment variable LANG: es_GT.UTF-8
VM arguments: [-Duser.home=${HOME}]

Last errors/warnings:
- 02091.806 E: Handled by bug report queue: java.nio.file.InvalidPathException: Malformed input or input contains unmappable characters: /home/<user.name>/M��sica
- 02091.859 E: Handled by bug report queue: java.nio.file.InvalidPathException: Malformed input or input contains unmappable characters: /home/<user.name>/M��sica
- 02091.865 E: Handled by bug report queue: java.nio.file.InvalidPathException: Malformed input or input contains unmappable characters: /home/<user.name>/M��sica
- 02091.908 E: Handled by bug report queue: java.nio.file.InvalidPathException: Malformed input or input contains unmappable characters: /home/<user.name>/M��sica



=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: Basic L&F File Loading Thread (53)
java.nio.file.InvalidPathException: Malformed input or input contains unmappable characters: /home/gtevtas/M��sica
	at java.base/sun.nio.fs.UnixPath.encode(UnixPath.java:145)
	at java.base/sun.nio.fs.UnixPath.<init>(UnixPath.java:69)
	at java.base/sun.nio.fs.UnixFileSystem.getPath(UnixFileSystem.java:279)
	at java.base/java.nio.file.Path.of(Path.java:147)
	at java.base/java.nio.file.Paths.get(Paths.java:69)
	at java.desktop/sun.awt.shell.ShellFolder.getShellFolder(ShellFolder.java:247)
	at java.desktop/javax.swing.filechooser.FileSystemView.getFiles(FileSystemView.java:523)
	at java.desktop/javax.swing.plaf.basic.BasicDirectoryModel$FilesLoader.run0(BasicDirectoryModel.java:290)
	at java.desktop/javax.swing.plaf.basic.BasicDirectoryModel$FilesLoader.run(BasicDirectoryModel.java:279)
	at java.base/java.lang.Thread.run(Thread.java:834)

[skyper]

Closed as duplicate of #14596.
You need to set a proper LANG on your OS or use the start option --language.