Error building local installation folder (${path.join(baseFo

Error message

Error building local installation folder (${path.join(baseFolder, ...pathSegments)}): ${e}

What it means

_ensureAndJoinPath builds a directory chain under a base folder, creating each segment with mkdirSync if missing, and wraps any fs error in this Error naming the full joined path. It underpins the rush temp/recycler/package-install/common folders, so a failure here aborts the bootstrap before npm can run.

Source

Thrown at foundations/net/common/scripts/install-run.js:425

/**
 * Create missing directories under the specified base directory, and return the resolved directory.
 *
 * Does not support "." or ".." path segments.
 * Assumes the baseFolder exists.
 */
function _ensureAndJoinPath(baseFolder, ...pathSegments) {
    let joinedPath = baseFolder;
    try {
        for (let pathSegment of pathSegments) {
            pathSegment = pathSegment.replace(/[\\\/]/g, '+');
            joinedPath = path__WEBPACK_IMPORTED_MODULE_3__.join(joinedPath, pathSegment);
            if (!fs__WEBPACK_IMPORTED_MODULE_1__.existsSync(joinedPath)) {
                fs__WEBPACK_IMPORTED_MODULE_1__.mkdirSync(joinedPath);
            }
        }
    }
    catch (e) {
        throw new Error(`Error building local installation folder (${path__WEBPACK_IMPORTED_MODULE_3__.join(baseFolder, ...pathSegments)}): ${e}`);
    }
    return joinedPath;
}
function _getRushTempFolder(rushCommonFolder) {
    const rushTempFolder = process.env[RUSH_TEMP_FOLDER_ENV_VARIABLE_NAME];
    if (rushTempFolder !== undefined) {
        _ensureFolder(rushTempFolder);
        return rushTempFolder;
    }
    else {
        return _ensureAndJoinPath(rushCommonFolder, 'temp');
    }
}
/**
 * Compare version strings according to semantic versioning.
 * Returns a positive integer if "a" is a later version than "b",
 * a negative integer if "b" is later than "a",
 * and 0 otherwise.

View on GitHub (pinned to 63e28dc964)

Solutions

Set RUSH_TEMP_FOLDER to a writable directory to relocate the temp root.
Check ownership/permissions of ~/.rush and <repo>/common/temp; chown/chmod (fix dirs previously created with sudo: sudo chown -R $(whoami) ~/.rush).
Remove a conflicting file at the reported joined path so mkdir can create a folder there.
Free disk space or remount the volume read-write if the cause is ENOSPC/EROFS.

Example fix

// before
sudo rush install   # creates ~/.rush owned by root
rush install        # Error building local installation folder (/home/me/.rush/...): EACCES
// after
sudo chown -R $(whoami) ~/.rush
rush install

Defensive patterns

Strategy: validation

Validate before calling

const base = process.env.RUSH_TEMP_FOLDER ?? path.join(os.homedir(), '.rush')
fs.mkdirSync(base, { recursive: true })
fs.accessSync(base, fs.constants.W_OK) // throws EACCES early with a clear path

Try / catch

try {
  ensureRushFolders()
} catch (e) {
  if (e.message.startsWith('Error building local installation folder')) {
    const p = e.message.match(/\(([^)]+)\)/)?.[1]
    console.error(`Cannot create ${p} — check ownership/permissions or set RUSH_TEMP_FOLDER`)
  }
  throw e
}

Prevention

Never run rush installs under sudo; if you did, chown ~/.rush back to your user.
Point RUSH_TEMP_FOLDER at a known-writable dir in CI and containers.
Ensure the target path is not occupied by a regular file before bootstrap.
Monitor disk space on volumes hosting the rush temp folders.

When it happens

Trigger: _getRushTempFolder / rushRecyclerFolder / packageInstallFolder / rushCommonFolder call _ensureAndJoinPath and an fs operation fails: EACCES creating the folder, EPERM, path exists as a FILE (EEXIST/ENOTDIR), disk full, or read-only volume.

Common situations: RUSH_TEMP_FOLDER env var points somewhere unwritable; ~/rush or the repo's common/temp owned by root after a sudo run; the target path exists as a file; CI runners with read-only HOME.

Related errors

AI-assisted analysis of hcengineering/platform@63e28dc964 (2026-08-29). Data as JSON: /api/errors/7c762e0b02ae9398. Report an issue: GitHub.