src/vs/platform/backup/electron-main/backupMainService.ts/BackupMainService/convertToEmptyWindowBackupSync
class BackupMainService:	private convertToEmptyWindowBackupSync(backupPath: string): boolean {

		// New empty window backup
		let newBackupFolder = this.getRandomEmptyWindowId();
		while (this.emptyWindows.some(emptyWindow => !!emptyWindow.backupFolder && this.backupPathComparer.isEqual(emptyWindow.backupFolder, newBackupFolder))) {
			newBackupFolder = this.getRandomEmptyWindowId();
		}

		// Rename backupPath to new empty window backup path
		const newEmptyWindowBackupPath = this.getBackupPath(newBackupFolder);
		try {
			fs.renameSync(backupPath, newEmptyWindowBackupPath);
		} catch (error) {
			this.logService.error(`Backup: Could not rename backup folder: ${error.toString()}`);
			return false;
		}
		this.emptyWindows.push({ backupFolder: newBackupFolder });

		return true;
	}