This error occurs when the scalar command cannot register a Git repository for optimized maintenance and background operations. Common causes include missing 'origin' remote, corrupted scalar configuration, or permission issues. The fix typically involves ensuring a valid remote exists or cleaning up stale scalar entries.
The "failed to register repository with scalar" error indicates that Git's Scalar tool could not add your repository to its list of managed enlistments. Scalar is a tool that helps Git scale to very large repositories by enabling optimized features like partial clone, background maintenance (prefetch, commit-graph, loose-objects), and filesystem monitoring. When you run `scalar register`, Scalar attempts to: 1. Validate that the directory is a Git repository 2. Find and record the remote "origin" URL 3. Add the repository path to the global Git config under `scalar.repo` 4. Configure recommended Git settings for large repos 5. Start background maintenance tasks This error typically means one of these steps failed. The most common cause is a missing or renamed "origin" remote, but it can also occur due to: - **Manual enlistment deletion** - If you deleted a previously registered repository without unregistering it first - **Corrupted scalar configuration** - Invalid entries in your global Git config - **Permission issues** - Cannot write to Git config or the repository - **Directory structure issues** - Scalar expects a specific layout when using `scalar clone` Understanding why registration failed helps determine the correct fix.
The most common cause of this error is a missing or renamed "origin" remote. Scalar requires a remote named "origin" to exist.
Check your remotes:
# List all configured remotes
git remote -v
# If output shows no 'origin', that's the problem
# You might see something like:
# github https://github.com/user/repo.git (fetch)
# github https://github.com/user/repo.git (push)Add or rename the origin remote:
# If you have no remotes at all, add origin
git remote add origin https://github.com/user/repo.git
# If you renamed origin to something else, rename it back
git remote rename github origin
# Or add origin as an alias to your existing remote
git remote add origin https://github.com/user/repo.gitAfter fixing the remote:
# Try registering again
scalar registerIf you previously deleted repositories that were registered with Scalar, you may have stale entries in your Git config.
View current scalar registrations:
# List all registered scalar repositories
scalar list
# Or check the Git config directly
git config --global --get-all scalar.repoRemove entries for deleted repositories:
If you're using Git 2.39 or later, scalar can automatically clean up stale entries:
# Reconfigure all registered repos (auto-removes missing ones)
scalar reconfigure -aFor older Git versions, manually remove stale entries:
# Remove a specific stale entry
git config --global --unset scalar.repo "/path/to/deleted/repo"
# Or edit the config file directly
git config --global --edit
# Find and remove lines like:
# [scalar]
# repo = /path/to/deleted/repoThen try registering your repository again:
scalar registerEnsure you're running scalar in a valid Git repository with proper permissions.
Check if you're in a Git repository:
# Should output your repository path
git rev-parse --show-toplevel
# If you get "not a git repository", you're in the wrong directoryCheck Git config file permissions:
# View global config location
git config --global --list --show-origin | head -1
# On Unix/macOS, check permissions
ls -la ~/.gitconfig
# Ensure you can write to it
touch ~/.gitconfig && echo "Write permission OK"For worktrees - register the main repository:
# If you're in a worktree, find the main repo
git worktree list
# Navigate to the main repository and register there
cd /path/to/main/repo
scalar registerCheck for repository corruption:
# Verify repository integrity
git fsck
# If errors appear, you may need to repair or re-cloneIf the repository was partially registered, unregister it first and try again.
Unregister the repository:
# Navigate to your repository
cd /path/to/your/repo
# Unregister (ignore errors if not registered)
scalar unregister || trueClear any cached scalar settings in the repo:
# Check local scalar config
git config --local --list | grep scalar
# Remove local scalar settings if present
git config --local --unset-all scalar.repo 2>/dev/nullRe-register the repository:
# Ensure origin exists
git remote -v
# Register with scalar
scalar register
# Verify registration
scalar listIf using a specific enlistment path:
# Register a specific directory
scalar register /path/to/your/repoScalar functionality has improved significantly in recent Git versions. Many issues are fixed in newer releases.
Check your current Git version:
git --version
# Git 2.39+ includes many scalar improvementsUpdate Git:
On macOS (Homebrew):
brew update
brew upgrade gitOn Windows:
# Using Git for Windows built-in updater
git update-git-for-windows
# Or download from https://git-scm.com/download/winOn Ubuntu/Debian:
sudo add-apt-repository ppa:git-core/ppa
sudo apt update
sudo apt install gitOn Fedora:
sudo dnf install gitKey improvements in recent versions:
- Git 2.39: scalar reconfigure -a auto-removes stale entries
- Git 2.38: Built-in FSMonitor support with scalar
- Git 2.35: Better handling of manually deleted enlistments
If scalar registration fails due to filesystem monitoring issues, you may need to reset FSMonitor state.
Check FSMonitor status:
# See if fsmonitor is enabled
git config core.fsmonitor
# Check fsmonitor hook version
git config core.fsmonitorhookversionReset FSMonitor state:
# Clear FSMonitor data from the index
git update-index --no-fsmonitor
git update-index --fsmonitor
# Or disable and re-enable
git config core.fsmonitor false
git config core.fsmonitor trueIf using Watchman:
# Check if watchman is running
watchman version
# Clear watchman state for this repo
watchman watch-del "$(git rev-parse --show-toplevel)"
watchman watch-project "$(git rev-parse --show-toplevel)"Use built-in FSMonitor instead of Watchman:
# Disable external watchman hook
git config --unset core.fsmonitor
# Enable built-in FSMonitor (Git 2.37+)
git config core.fsmonitor true
git config core.untrackedcache trueThen try registering again:
scalar registerUnderstanding Scalar Registration:
Scalar manages several Git optimizations:
- Partial clone - Fetches only needed objects, reducing clone time
- Background prefetch - Pre-fetches commits hourly to speed up fetch/pull
- Commit-graph - Maintains commit-graph file for faster log/blame operations
- Loose-objects maintenance - Periodic cleanup of loose objects
- Incremental repack - Multi-pack index for optimized packfile access
- FSMonitor - Filesystem monitoring for faster status/add commands
Configuration Locations:
Scalar stores registration data in the global Git config:
[scalar]
repo = /path/to/repo1
repo = /path/to/repo2Per-repository settings are stored in the local .git/config.
Scalar Clone vs Register:
- scalar clone - Clones with partial clone enabled and registers automatically
- scalar register - Registers an existing repository for scalar management
When using scalar clone, the directory structure is:
repo-name/
src/ <- This is the actual Git working directoryRunning scalar register from inside src/ uses the parent as the enlistment root.
macOS and Linux Considerations:
After upgrading Scalar or Git, you may need to re-register repositories:
# Re-register all repos after upgrade
scalar reconfigure -aOn macOS, the built-in FSMonitor daemon may need to be restarted:
# Stop FSMonitor daemon
git fsmonitor--daemon stop
# It will restart automatically on next git commandTroubleshooting with Verbose Output:
# Enable trace output
GIT_TRACE=1 scalar register
# For more detail on scalar operations
GIT_TRACE_PACKET=1 GIT_TRACE=1 scalar register 2>&1 | tee scalar-debug.logEnterprise Environments:
In corporate environments with restricted permissions:
- Ensure you have write access to ~/.gitconfig
- Check if Group Policy restricts Git config modifications
- Verify antivirus isn't blocking Git or FSMonitor processes
- Some VPNs or security software may interfere with background maintenance tasks
Alternative to Scalar:
If scalar continues to fail, you can manually enable the optimizations:
# Enable partial clone for future clones
git clone --filter=blob:none <url>
# Enable commit-graph
git config core.commitGraph true
git commit-graph write --reachable
# Enable FSMonitor
git config core.fsmonitor true
git config core.untrackedcache true
# Enable multi-pack index
git config core.multiPackIndex true
git multi-pack-index writewarning: BOM detected in file, this may cause issues
UTF-8 Byte Order Mark (BOM) detected in file
fatal: Server does not support --shallow-exclude
Server does not support --shallow-exclude
warning: filtering out blobs larger than limit
Git partial clone filtering large blobs warning
fatal: Server does not support --shallow-since
Server does not support --shallow-since in Git
kex_exchange_identification: Connection closed by remote host
Connection closed by remote host when connecting to Git server