If there are lost or damaged files after verification, you can try to repair them. There are something to do, before repair and after failed repair.
Way to start MultiPar after selecting a recovery file
If you have set options in "System settings" page, you can start MultiPar by selecting a recovery file. This way is easier than opening a recovery file by pushing "Open" button after you start MultiPar. Even when there are multiple recovery files of same set, you must select one of them. If you happen to select multiple recovery files, Create window may open, or multiple Verify windows will open.
- When you have checked "Associate with ... files";
- If you right-click after selecting a recovery file over Windows Explorer, right-click menu appears. Then, you click "Open with MultiPar" on the menu. Or, you simply double-click the recovery file, which you want to open.
- When you have checked "Integrate MultiPar into Shell";
- If you right-click after selecting a recovery file over Windows Explorer, right-click menu appears. When you select "MultiPar" on the menu, sub-menu appears. Then, you click "Verify Recovery Volume" on the sub-menu.
- When you have checked "Create MultiPar icon on desktop";
- You select a recovery file and Drag & Drop it onto the MultiPar icon.
- When you have checked "Add MultiPar icon to [SendTo] menu";
- If you right-click after selecting a recovery file over Windows Explorer, right-click menu appears. When you select "SendTo" on the menu, sub-menu appears. Then, you click "MultiPar" on the sub-menu.
Prepare to repair damaged files
While you may verify written files on read-only media like CD-R or DVD-R, you cannot repair damaged files immediately. When you repair files, you need to copy those files on HDD. Even if they are damaged files or fragments of unknown filename, you should bring all source files and recovery files to a folder on HDD. To retrieve as many data as you can from damaged media, you would better use "File Salvager software". There are many shareware and freeware for the purpose. Because "Data Recovery service" by a specialist company requires more money, it's the last way to restore important data.
If you cannot verify by incomplete PAR2 files
When some vital packets are missing in a PAR2 file, it will be hard to verify or repair. But all kinds of packets may exist in multiple PAR2 files. Because MultiPar will search other PAR2 files of same base filename in the folder automatically, you should set same base filename for all PAR2 files of the same recovery set. (Base filename is a filename except extension and volume number.) When other PAR2 files are put in another folder, or are renamed to different base filename, you must add them manually by "Add" button.
If you cannot repair by a lack of available blocks
Get more blocks as possible as you can. If there is a same source file on different location, you should copy it or add it by "Add" button. You need to find more blocks from the damaged media. If you cannot recognize fragments are pieces of which source file, you select "Additional verification" at "Verification level". If there are old files of modified version in a previous backup, it is worth to add them.
When a transported file had been damaged already, you cannot salvager lost data on your side. If there are other recovery files, you get them, too. If there is same file on another site, you may get it again. Or, you may ask someone to give another set of recovery files.
If you failed to repair, even when you have enough blocks
Mostly this is caused by "exclusive file access" or "limited privilege". Because there are some applications which forbid others opening or modifying files, you should close them. When status of a damaged file became "Locked" after failed repair, the file is being used by another application. Of course, you cannot repair (modify) a system file, which is protected by OS. When repair was failed by a fault of PAR1/2 specifications, you may solve the problem by getting one more available block.
Some PAR2 clients (like old YencPowerPost) created incompatible non-standard PAR2 files. They happened to allocate too many blocks on big files. Those corrupt PAR2 files are almost useless for repair. For example, you cannot recover extra blocks over than the limit. Be careful in using very old PAR2 files over UseNet.