Crash Assistant in FTB Skies 2

Same as in the All the Mods 10 8.1 guide

Crash Assistant is a crash-helper mod. When Minecraft crashes, it pops up a window that immediately shows the affected game and launcher logs, crash reports and hs_err files. From there you can upload everything with one click and copy a link to paste into Discord or GitHub. The pack ships version 1.11.12.^[1][2]

It is client-only, so on a server it does nothing.^[1]

Who it is for

It is for anyone who crashes and wants to know why, and for people who help with support. You get a formatted, ready-to-paste report, and anyone helping you gets current logs without having to ask for more files. The mod's author says more than 75% of issues are common and easily solvable, and the analysis aims to cut that support load.^[1]

What it does for you

• Analyzes logs for many known crash causes. When it finds one, it shows a dialog with a description and a detailed fix. Examples include out-of-memory errors, duplicated mods, Mixin conflicts, and GPU driver problems.^[1]
• Warns you if Minecraft is running on an integrated GPU when a dedicated one is available, and offers a one-click Auto-Fix button on Windows.^[1]
• Warns you if your CPU is one of the Intel 13th/14th generation models known to have a critical stability bug.^[1]
• Includes analysis tools in the GUI menu, such as a Package/Class Finder that shows which mod contains a given Java class or package.^[1]
• Saves the modlist, and for modpack players it lists the mods you added, removed or updated compared with the official list. You can also save it manually with the /crash_assistant modlist save command.^[1]

It runs as a separate process that waits for the Minecraft JVM to stop. It also loads very early, so it can catch crashes during startup.^[1]

Where it fits in the pack

Crash Assistant is a utility rather than a gameplay mod, so it adds no progression of its own. You don't need to unlock or craft anything. It is there when something goes wrong.^[1]

Unverified The sources I was given show no quests or ATM Star path involvement for this mod, and no in-jar guidebook was found for it.

Crash Assistant is a safety net that waits in the background and only matters when Minecraft crashes. When that happens it opens a window showing the affected game and launcher logs, crash reports or hs_err files, and lets you upload them in one click and copy the link for easier reporting.^[1]

The mod is client-only, so on a server it does nothing.^[1]

What to know before your first crash

1. Leave the analysis on. In this pack, log analysis (analysis.enabled) and the analysis tools (analysis_tools.enabled) are both enabled. When the mod recognises a known crash reason, it shows a dialog with a description of the problem and a solution.^[1][3]
2. Read the recommendation. The first time a crash reason is shown, the OK button is delayed by 10 seconds, set by analysis.first_show_delay, so you actually read it.^[3]
3. Know what gets blamed. By default, when the mod runs in modpack mode for the end user, it does not blame mods that were part of the original modpack, only mods that were added or updated afterwards. In this pack analysis.trigger_on_original_modpack_mods is false.^[3]
4. Accept the privacy policy. Before you upload your first log, you have to accept a privacy policy, because general.enable_privacy_policy_acceptance is true in this pack.^[3]
5. Use Upload All when asking for help. This pack keeps that button visible (gui_customisation.disable_upload_all_button is false). Logs are uploaded to mclo.gs, and general.upload_to is set to wrap the link for gnomebot.dev for better formatting.^[3]
6. Use the Request Help button when you need support. It opens the link set in general.help_link.^[3]

Handy extras

• The GUI supports drag and drop. You can drag log files straight out of it, or drag all logs at once from the "Available log files:" label.^[1]
• The mod warns you if Minecraft is running on an integrated GPU when a dedicated one is available, and it includes auto-fixes for many common issues.^[1]
• This pack generates its own launcher log with the stderr stream (general.generate_own_launcher_log is true), since many launchers do not save it.^[3]
• A crash command is enabled in this pack. To make sure you really want to crash the game, you have to run it again within 10 seconds (crash_command.enabled and crash_command.seconds).^[3]

There are no machines, multiblocks, power or fluids here. Crash Assistant is a client-only crash helper: when Minecraft crashes it shows a window with the affected logs, analyzes them and helps you report the problem. On a server it does nothing. This section walks through how that flow works and how the pack has it set up.^[1]

What happens after a crash

The window immediately lists the affected game and launcher logs, crash reports and hs_err files. From there you can upload them, copy the link and do other reporting actions in one click. It also supports drag and drop, so you can pull files straight out of the window, or drag every log at once from the "Available log files:" label.^[1]

In this version of the pack, the window also appears if the game dies during mod loading and the FML error screen is shown, because general.show_on_fml_error_screen is on. A Windows event log alone does not count as a crash, since general.win_event_is_crash is off. When you start a new Minecraft instance, any old Crash Assistant window still open gets closed (general.kill_old_app).^[3]

As the pack currently ships it, the mod also writes its own stderr log. With general.generate_own_launcher_log on, it creates logs/stderr_stream.log, which helps because many launchers do not save that stream. The individual upload buttons only unlock once the mod has finished scanning for terminated processes (general.prevent_upload_buttons_delay is false), which nudges people toward the Upload All button.^[3]

Log analysis

The mod checks the logs against many known crash reasons. When it finds one, it shows a dialog with a description of the problem and a detailed solution. It covers JVM crashes (hs_err files, such as GPU driver DLL problems or the system running out of memory), regular logs and crash reports, and Windows event logs.^[1]

• OutOfMemoryError: Minecraft ran out of allocated RAM.^[1]
• DuplicatedMods: multiple versions of the same mod are installed.^[1]
• Create6Addons: a Create version and one of its addons are incompatible, with a button to find all incompatible mods.^[1]
• MixinApply: crashes from Mixin conflicts or errors, including missing class detection.^[1]
• UnsupportedClassVersion: a mod was compiled with a newer Java than the one in use.^[1]
• WasClosedByWindows (Windows event log): the game froze and was terminated by the OS.^[1]

After an upload, every supported log is also run through the Codex logs analyzer from mclo.gs. For unclear Codex messages such as an erroring block or entity, the mod shows its own detailed how-to-fix guide.^[1]

In this version of the pack, analysis is on (analysis.enabled) and no reasons are blacklisted (analysis.blacklisted_reasons is empty). When a crash reason is shown for the first time, the OK button is delayed by 10 seconds so you actually read the advice (analysis.first_show_delay). When a player runs the pack, the analysis does not blame mods that were part of the original pack, only mods added or updated afterwards (analysis.trigger_on_original_modpack_mods is false).^[3]

The GUI menu also has analysis tools, enabled in this version of the pack through analysis_tools.enabled with none blacklisted. Among them are a Create/Epic Fight addons compatibility scan and an MCreator Mod Detector that lists mods made with MCreator. The mod also warns you when Minecraft runs on an integrated GPU although a dedicated one is available, and offers auto-fixes for many common issues.^[1][3]

The Upload All message

The Upload All button builds a ready-to-post message. As the pack currently sets it, the layout (generated_message.message_structure) puts a header, optional custom text, the logs, the problematic frame from hs_err, the analysis result and the modlist changes in that order. Each log line starts with the prefix "### " (generated_message.prefix) so links are easier to hit on mobile, and logs are separated by a vertical bar with spaces around it. ANSI colouring is off (generated_message.color_message), and both the analysis result names and the problematic frame are included.^[3]

Logs too large for a single upload are split into a head and a tail. In this version of the pack, when you copy a link from an individual upload button, you get a dialog to pick head or tail, because copied_links.skip_split_dialog is false. The text under the "crashed!" title and the warning shown after pressing Upload All are both empty.^[3]

Modlist tracking

The mod can keep a modlist.json so it knows which mods were in the original pack and which an end user changed. It is enabled in the pack (modpack_modlist.enabled). When a listed modpack creator launches the game, the file is rewritten on every launch, so it is not forgotten before publishing (modpack_modlist.auto_update). The creators listed are FTB Team, Saereth and Artpoke_ (modpack_modlist.modpack_creators). To save manually instead, disable auto update and use the /crash_assistant modlist save command.^[3]

In this version of the pack, a generated modlist.txt is added to the logs and the modloader jar name is recorded, so a changed loader version is easy to spot. Datapacks and resource packs are not added to the modlist. The "too many changes" warning is off, since its count is -1 (too_many_changes_warning.count).^[3]

Unverified The actual contents of the pack's modlist.json are in config/crash_assistant/modlist.json, which the sources here do not show.

Other features in the pack

• Crash command: enabled in the pack's current config, and you must run it again within 10 seconds to confirm you really want to crash the game (crash_command.seconds).^[3]
• Simple mode: off in this version of the pack (simple_mode.enabled). When on, the GUI hides the logs behind a single "Show Logs (Expert Mode)" button, but modpack creators still see the logs.^[3]
• Scripts: enabled in this version of the pack, with the Scripts IDE available in the GUI. The startup scripts log is only added to the log list when it contains [ERROR] (scripts.attach_startup_scripts_log_only_on_error).^[3]
• Crash report fix: the pack's current config enables a patch for vanilla crash MC-307905, which stops crash report generation from itself crashing in rare cases (patches.MC307905).^[3]
• Support text: in this version of the pack the GUI uses Discord wording, "FTB Discord" and the #java-support channel (general.formulation_type). The piracy warning is off (piracy.enabled).^[3]

Crash Assistant is client-only, so none of these options do anything on a server. They only matter for the crash window you see on your own game. Here are the options you're most likely to care about and how this pack currently sets them.^[1][3]

Who gets help, and where

• text.modpack_name is currently "FTB Skies 2". It's the name shown in the crash window and in the generated message.^[3]
• text.support_name is currently "FTB Discord" and text.support_place is currently "#java-support". These fill in the help text, and general.formulation_type is set to "DISCORD", so the wording talks about joining the Discord.^[3]
• general.help_link currently points to FTB's modpack issues page on GitHub. The Request Help button opens this link in your browser.^[3]
• general.upload_to is currently "gnomebot.dev". Logs are still uploaded to mclo.gs, and this option only wraps the link for better formatting.^[3]

Uploading and privacy

• general.enable_privacy_policy_acceptance is currently true, so you have to accept the privacy policy before your first log upload.^[3]
• general.generate_own_launcher_log is currently true. It writes the stderr stream to a log file, which helps because many launchers don't save that output.^[3]
• general.show_on_fml_error_screen is currently true, so the window also appears when the game fails during mod loading.^[3]

Analysis and warnings

• analysis.enabled is currently true and analysis.first_show_delay is currently 10. The OK button is delayed by 10 seconds the first time a crash reason is shown, so you actually read the advice.^[3]
• analysis.trigger_on_original_modpack_mods is currently false. When you're the end user, the analysis won't blame mods that shipped with the original pack, only ones you added or updated.^[3]
• piracy.enabled is currently false in this pack, so the piracy warning isn't shown. piracy.delay is 10 if it were on.^[3]
• too_many_changes_warning.count is currently -1, which disables the "too many changes" warning.^[3]

The crash command and simple mode

crash_command.enabled is currently true. The command has to be run again within crash_command.seconds seconds, which is 10 here, to confirm that you really want to crash the game. simple_mode.enabled is currently false, so the window starts in the full view with logs visible.^[3]

Modlist tracking

modpack_modlist.enabled and modpack_modlist.auto_update are both true. The modlist file is rewritten on launch, but only when the game is started by someone listed in modpack_modlist.modpack_creators: "FTB Team", "Saereth" and "Artpoke_". That file is how the mod can tell which mods you changed.^[3]

FTB Skies 2 1.22.0 ships Crash Assistant 1.11.12, and the mod has been in the pack since 1.0.1 or earlier. Below are the notable changes from the mod's own changelogs, newest first. Many entries cover other Minecraft versions and loaders too, so not everything applies to this pack.^[4]

1.11.12 (the version in this pack)

• Persistent mod-list history for launches. Each snapshot records whether the game only started, reached the title screen, joined a world, crashed during gameplay, or closed without a crash. The main comparison now picks a suitable previous launch dynamically.^[5]
• A filterable, sortable two-pane history browser for comparing any two launch snapshots. Comparisons involving Current keep the Remove, Enable/Disable, Revert, Restore and Show Folder actions, while snapshot-to-snapshot comparisons are read-only.^[5]
• You can import modlist.txt data from a file or the clipboard and compare it with Current.^[5]
• Fixed comparisons missing an updated mod when its JAR was replaced without changing the file name or declared version. If both snapshots have a comparable CurseForge or Modrinth hash and it differs, the mod now counts as updated.^[5]
• Upload All messages now include non-empty mod list differences and unavailable-reference notices, and unchanged comparisons are not uploaded.^[5]
• The general.upload_to option was replaced by general.wrap_link, and the old value is not migrated. By default, copied log links now open in the new kostromdan.dev log viewer instead of gnomebot.dev.^[5]
• The new log viewer is a fork of gnomebot.dev made for Crash Assistant. It adds a switcher between logs from the same launch, multi-line range links, quick links to the first error, last error and end of file, a Download All button that saves every log from the launch as one ZIP, and an option to wrap long lines.^[5]

Recent releases before it

• 1.11.11: bumped JEXL to 3.7.0 and fixed JEXL scripts not being able to access allowed static fields of allowed classes. Also fixed an issue where the CurseForge API will require an API key since July 15 to download mods from its CDN.^[6]
• 1.11.10: ported to 26.2 for NeoForge and Fabric, fixed the Better Compatibility Checker config format, and fixed compatibility with the Radiance mod.^[7]
• 1.11.9: fixed a race condition during the Crash Assistant GUI start. On 1.19+, it patches vanilla issue MC-307905, which could prevent crash reports from generating. The patch is enabled by default and can be disabled in the config.^[8]
• 1.11.8: hotfix for a piracy warning redesign that hid the Join Discord button even for licensed players.^[9]
• 1.11.3: initial release for legacy-fabric versions, and fabric-api is no longer required on Fabric 1.13.2 and higher.^[10]

Releases from 1.10.6 to 1.10.27

• 1.10.24: the Mod List Difference feature became an interactive tool with Added, Updated and Removed tables, CurseForge and Modrinth integration, and Revert Update and Restore actions. If a mod blocks third-party downloads, you get a drag and drop fallback dialog.^[11][12]
• 1.10.25: fixed out-of-memory errors from the new hashing by switching to a streaming approach with constant memory use.^[11][12]
• 1.10.27: added GZIP compression for McLogs API uploads, reducing payload size and upload times by up to 100x.^[11]
• 1.10.23: added an option to skip the split dialog for large logs and a Simple Mode that hides logs behind a button, disabled by default.^[11][12]
• 1.10.20: Crash Assistant now generates stderr_stream.log with the Minecraft process's stderr output, with a config option to turn it off.^[13]
• 1.10.21: added new log analyses such as JnaPermissionIssue and AzureLibAddons.^[13]
• 1.10.6: redesigned the language provider, with new general.priority_lang_for_overrides and general.generate_localization_overrides_folder_with_readme options.^[14]

Older releases

In 1.9.15 the mod was backported so that it is available for all modloaders on every version from 1.16.5 to 1.21.8 without gaps. The releases just before it added analyses such as MissingIndium, ModuleFind and UnsupportedClassVersion, and the first releases for 1.12.2 and 1.7.10.^[15]