Makhaon dicom dump allows validating, editing and viewing DICOM and dicomdir files. All standard tags (under standard DICOM 2014c) and their VR are supported. Correctly parse tags with VM (Value Multiplicity). Can add, change, delete any tag.
Microsoft facilitates an inbuilt tool named scanpst.exe for OST to PST file conversion, when OST file becomes inaccessible. But it is not capable of handling major issues, so user has to rely on external source to recover the damaged file.