arduino/Arduino · error · IOException

Can't extract file {outputFile}, file already exists!

Error message

Can't extract file {outputFile}, file already exists!

What it means

When an archive entry is a regular file (or link/symlink) and a file already exists at the destination path while overwrite is false, extract() throws this IOException. It protects existing files from being silently replaced during library installation.

Source

Thrown at arduino-core/src/cc/arduino/utils/ArchiveExtractor.java:215

          // Symbolic links are referenced with relative paths
          outputLinkedFile = new File(linkName);
          if (outputLinkedFile.isAbsolute()) {
            System.err.println(I18n.format(tr("Warning: file {0} links to an absolute path {1}"), outputFile, outputLinkedFile));
            System.err.println();
          }
        }

        // Safety check
        if (isDirectory) {
          if (outputFile.isFile() && !overwrite) {
            throw new IOException("Can't create folder " + outputFile + ", a file with the same name exists!");
          }
        } else {
          // - isLink
          // - isSymLink
          // - anything else
          if (outputFile.exists() && !overwrite) {
            throw new IOException("Can't extract file " + outputFile + ", file already exists!");
          }
        }

        // Extract the entry
        if (isDirectory) {
          if (!outputFile.exists() && !outputFile.mkdirs()) {
            throw new IOException("Could not create folder: " + outputFile);
          }
          foldersTimestamps.put(outputFile, modifiedTime);
        } else if (isLink) {
          hardLinks.put(outputFile, outputLinkedFile);
          hardLinksMode.put(outputFile, mode);
        } else if (isSymLink) {
          symLinks.put(outputFile, linkName);
          symLinksModifiedTimes.put(outputFile, modifiedTime);
        } else {
          // Create the containing folder if not exists
          if (!outputFile.getParentFile().isDirectory()) {

View on GitHub (pinned to a0df6e0e83)

Solutions

1. Call extract with overwrite=true when intentional replacement (upgrade/reinstall) is desired
2. Remove the existing library folder from libraries/ (or the destination) before extracting
3. Catch this IOException and prompt the user whether to overwrite, then retry with overwrite enabled

Example fix

// before
try {
  archiveExtractor.extract(archive, dest, 1); // throws if files exist
} catch (IOException e) { /* install aborts */ }
// after
archiveExtractor.extract(archive, dest, 1, true); // explicit overwrite on reinstall

// check for existing files at archive entry paths before extracting
if (destFolder.exists()) {
  try (TarArchiveInputStream in = new TarArchiveInputStream(new FileInputStream(archiveFile))) {
    TarArchiveEntry e;
    while ((e = in.getNextTarEntry()) != null) {
      if (!e.isDirectory() && new File(destFolder, e.getName()).exists()) throw new IllegalStateException("Already installed: " + e.getName());
    }
  }
}

try { extractor.extract(archive, dest, 1); } catch (IOException e) { if (e.getMessage().startsWith("Can't extract file")) { boolean ok = askUserToOverwrite(); if (ok) extractor.extract(archive, dest, 1, true); } else { throw e; } }

When it happens

Trigger: extract() into a destination folder that already contains a file with the same relative path as an archive entry, with the overwrite flag false (default).

Common situations: Reinstalling the same library version over an existing installation; Library Manager update flow racing with a manually installed copy; retrying a failed extraction that partially completed without overwrite enabled.

Understand the failure class

Background: "already exists" / EEXIST / FileAlreadyExistsException: what the 'file already exists' error means and how to fix it — this error's family across 37 libraries.

Related errors

• Can't create folder {outputFile}, a file with the same name
• Can't download {0}: invalid filename or exinsting directory
• no headers files (.h) found in {0}
• 'arch' folder is no longer supported! See http://goo.gl/gfFJ
• 'Unable to list files of library in ' + libFolder

AI-assisted analysis of arduino/Arduino@a0df6e0e83 (2026-09-06). Data as JSON: /api/errors/74433de653926166. Report an issue: GitHub.