The string "--" is not permitted within comments

I downloaded ganttproject today for a test and get this error right away when starting the application the first time and after that with each first “new project” click, but not on subseqental “new project” clicks.

My System is a MacOS 12.2.1 on M1

I have set Times new Roman as App and chart Font but that did not help .

What can i do?

/Users/<myuser>/ganttproject.log

GanttProject 3.2.3210
Settings file:
	location: /Users/<myuser>/.ganttproject
	size:5514
	is readable: true
java.class.path: /Applications/GanttProject.app/Contents/app:/Applications/GanttProject.app/Contents/app/eclipsito.jar
java.home: /Applications/GanttProject.app/Contents/runtime/Contents/Home
java.ext.dirs: null
java.io.tmpdir: /var/folders/sf/yfrzcwy91jz9m0cc0y82g_k00000gn/T/
java.runtime.version: 11.0.13+8-LTS
java.vendor: BellSoft
java.vm.name: OpenJDK 64-Bit Server VM
java.vm.vendor: BellSoft
java.vm.version: 11.0.13+8-LTS
os.arch: x86_64
os.name: Mac OS X
os.version: 12.2.1
sun.java.command: com.bardsoftware.eclipsito.Launch --verbosity 4 --version-dirs plugins:~/.ganttproject.d/updates --app net.sourceforge.ganttproject.GanttProject
user.country: <myCountry>
user.dir: /Applications/GanttProject.app/Contents/app
user.home: /Users/<myuser>
user.language: <myLanguage>
user.timezone: Europe/<myTZ>

Warning: the fonts "Times" and "Times" are not available for the Java logical font "Serif", which may have unexpected appearance or behavior. Re-enable the "Times" font to remove this warning.
Warning: the fonts "Times" and "Times" are not available for the Java logical font "Serif", which may have unexpected appearance or behavior. Re-enable the "Times" font to remove this warning.
Feb. 27, 2022 4:53:34 VORM. biz.ganttproject.LoggerImpl debug
FEIN: Creating main frame...
Feb. 27, 2022 4:53:34 VORM. biz.ganttproject.LoggerImpl debug
FEIN: 1. loading look'n'feels
Feb. 27, 2022 4:53:34 VORM. biz.ganttproject.LoggerImpl debug
FEIN: 2. loading options
Feb 27, 2022 4:53:35 AM biz.ganttproject.LoggerImpl debug
FINE: 3. creating menus...
Feb 27, 2022 4:53:35 AM biz.ganttproject.LoggerImpl debug
FINE: 4. creating views...
Feb 27, 2022 4:53:36 AM biz.ganttproject.LoggerImpl debug
FINE: 5. calculating size and packing...
Warning: the fonts "Times" and "Times" are not available for the Java logical font "Serif", which may have unexpected appearance or behavior. Re-enable the "Times" font to remove this warning.
Feb 27, 2022 4:53:37 AM biz.ganttproject.LoggerImpl debug
FINE: 6. changing language ...
Feb 27, 2022 4:53:37 AM biz.ganttproject.LoggerImpl debug
FINE: 7. first attempt to restore bounds
Feb 27, 2022 4:53:37 AM biz.ganttproject.LoggerImpl debug
FINE: 8. finalizing...
Feb 27, 2022 4:53:38 AM net.sourceforge.ganttproject.GPLogger log
INFO: Deleting old auto-save files
Feb 27, 2022 4:54:01 AM net.sourceforge.ganttproject.GPLogger logToLogger
WARNING: The string "--" is not permitted within comments.
org.xml.sax.SAXParseException; lineNumber: 19; columnNumber: 9; The string "--" is not permitted within comments.
	at java.xml/com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLScanner.scanComment(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanComment(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
	at java.xml/com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(Unknown Source)
	at java.xml/javax.xml.parsers.SAXParser.parse(Unknown Source)
	at net.sourceforge.ganttproject.io.XmlParser.parse(XmlParser.java:119)
	at net.sourceforge.ganttproject.calendar.GPCalendarProvider.readCalendar(GPCalendarProvider.java:82)
	at net.sourceforge.ganttproject.calendar.HolidayCalendarKt.loadCalendars(HolidayCalendar.kt:56)
	at net.sourceforge.ganttproject.calendar.GPCalendarProvider.readCalendars(GPCalendarProvider.java:91)
	at net.sourceforge.ganttproject.calendar.GPCalendarProvider.getInstance(GPCalendarProvider.java:96)
	at net.sourceforge.ganttproject.gui.projectwizard.WeekendConfigurationPage.createCalendarOption(WeekendConfigurationPage.java:196)
	at net.sourceforge.ganttproject.gui.projectwizard.WeekendConfigurationPage.<init>(WeekendConfigurationPage.java:139)
	at net.sourceforge.ganttproject.gui.projectwizard.NewProjectWizardWindow.addWeekendConfigurationPage(NewProjectWizardWindow.java:52)
	at net.sourceforge.ganttproject.gui.projectwizard.NewProjectWizard.createNewProject(NewProjectWizard.java:33)
	at net.sourceforge.ganttproject.gui.ProjectUIFacadeImpl.showNewProjectWizard(ProjectUIFacadeImpl.kt:279)
	at net.sourceforge.ganttproject.gui.ProjectUIFacadeImpl.createProject(ProjectUIFacadeImpl.kt:274)
	at net.sourceforge.ganttproject.GanttProject.newProject(GanttProject.java:520)
	at net.sourceforge.ganttproject.action.project.NewProjectAction.actionPerformed(NewProjectAction.java:44)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton.doClick(Unknown Source)
	at java.desktop/com.apple.laf.ScreenMenuItem.actionPerformed(Unknown Source)
	at java.desktop/java.awt.MenuItem.processActionEvent(Unknown Source)
	at java.desktop/java.awt.MenuItem.processEvent(Unknown Source)
	at java.desktop/java.awt.MenuComponent.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.MenuComponent.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)

Feb 27, 2022 4:54:01 AM net.sourceforge.ganttproject.GPLogger logToLogger
WARNING: The string "--" is not permitted within comments.
java.io.IOException: The string "--" is not permitted within comments.
	at net.sourceforge.ganttproject.io.XmlParser.parse(XmlParser.java:124)
	at net.sourceforge.ganttproject.calendar.GPCalendarProvider.readCalendar(GPCalendarProvider.java:82)
	at net.sourceforge.ganttproject.calendar.HolidayCalendarKt.loadCalendars(HolidayCalendar.kt:56)
	at net.sourceforge.ganttproject.calendar.GPCalendarProvider.readCalendars(GPCalendarProvider.java:91)
	at net.sourceforge.ganttproject.calendar.GPCalendarProvider.getInstance(GPCalendarProvider.java:96)
	at net.sourceforge.ganttproject.gui.projectwizard.WeekendConfigurationPage.createCalendarOption(WeekendConfigurationPage.java:196)
	at net.sourceforge.ganttproject.gui.projectwizard.WeekendConfigurationPage.<init>(WeekendConfigurationPage.java:139)
	at net.sourceforge.ganttproject.gui.projectwizard.NewProjectWizardWindow.addWeekendConfigurationPage(NewProjectWizardWindow.java:52)
	at net.sourceforge.ganttproject.gui.projectwizard.NewProjectWizard.createNewProject(NewProjectWizard.java:33)
	at net.sourceforge.ganttproject.gui.ProjectUIFacadeImpl.showNewProjectWizard(ProjectUIFacadeImpl.kt:279)
	at net.sourceforge.ganttproject.gui.ProjectUIFacadeImpl.createProject(ProjectUIFacadeImpl.kt:274)
	at net.sourceforge.ganttproject.GanttProject.newProject(GanttProject.java:520)
	at net.sourceforge.ganttproject.action.project.NewProjectAction.actionPerformed(NewProjectAction.java:44)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
	at java.desktop/javax.swing.DefaultButtonModel.setPressed(Unknown Source)
	at java.desktop/javax.swing.AbstractButton.doClick(Unknown Source)
	at java.desktop/com.apple.laf.ScreenMenuItem.actionPerformed(Unknown Source)
	at java.desktop/java.awt.MenuItem.processActionEvent(Unknown Source)
	at java.desktop/java.awt.MenuItem.processEvent(Unknown Source)
	at java.desktop/java.awt.MenuComponent.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.MenuComponent.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$4.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.desktop/java.awt.EventQueue$5.run(Unknown Source)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
	at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)

Thanks for reporting. I submitted a new issue to the tracker: https://github.com/bardsoftware/ganttproject/issues/2032