All windows named LTspice XVII must be closed before the Sync Release command can be activated. The user needs to establish the internet connection first. The LTspice XVII program will then download the master index file(release.log) from the LTC web server. The master index file contains the checksums for every file in the sub-directories. The local file's checksum is then calculated and checked against the one in the master index file. The file on the web server will then be downloaded automatically if there is a difference in checksum. LTspice XVII program files that were saved under the same name will be overwritten! Most of the macromodels are less than 3KB and can be transferred in a few seconds. During the update of the XVIIx64.exe(XVIIx86.exe on 32-bit systems), the new file is first copied to the Windows temp directory and the old XVIIx64.exe is overwritten after the download is complete. The old program is still preserved if the user cancels the file transfer. The changelog.txt file lists the program revisions.