This script tries to automatically fix empty files in a given Google Drive folder

Fix Empty Files.gs

/** Put the root folder ID here */
const ROOT_FOLDER_ID = "";

/** Set this to false to only see reports of fixed files and errors */
const VERBOSE = true;

/** Keeps track of how many files have been fixed */
let fixedFiles = 0;

/**
 * A function that deletes all versions of files in the given
 * folder and subfolders that are empty (aka 0 bytes)
 */
function fixAllFilesInFolder() {
  const folder = DriveApp.getFolderById(ROOT_FOLDER_ID);
  handleFolder(folder, 0);
}

/** 
 * Deletes all bad versions of files in folder and
 * calls itself with each subfolder to do the same
 */
function handleFolder(folder, treeRank, path = "") {
  const folderPath = `${path}/${folder.getName()}`;
  if (VERBOSE) Logger.log(`Searching ${folderPath}...`);

  fixFolderFiles(folder);
  const subFolders = folder.getFolders();

  while (subFolders.hasNext()) {
    subFolder = subFolders.next();
    handleFolder(subFolder, treeRank + 1, folderPath)
  }
}

/** Deletes all 'bad' versions of files in folder */
function fixFolderFiles(folder) {
  const files = folder.getFiles();

  while (files.hasNext()) {
    const file = files.next();
    const mimeType = file.getMimeType();

    if (file.getSize() === 0 && !mimeType.startsWith("application/vnd.google-apps.")) {
      Logger.log(`> ${file.getName()} is empty, fixing...`);
      deleteEmptyRevisions(file);
    }
  }
}

/** Delete 'bad' version of a file */
function deleteEmptyRevisions(file) {  
  const fileId = file.getId();  
  const revisions = Drive.Revisions.list(fileId);

  if (!revisions.items || revisions.items.length <= 1) {
    Logger.log(`> ${file.getName()} has no older revisions`);
    return;
  }

  // We don't want to remove the first revision, so we start at i = 1
  for (let i = 0; i < revisions.items.length; i++) {
      const revision = revisions.items[i];
      const fileSize = Number(revision.getFileSize());

      if (fileSize === 0) {
        Drive.Revisions.remove(fileId, revision.id);
      }
  }

  Logger.log(`> Fixed ${file.getName()} – ${++fixedFiles} fixed so far`);
}