Extra Unknown Space on iMac

hi all,
have 2011 imac, , i've noticed when click "get info" on hard drive says have used 260 gb of space on drive. find odd because when checked size of backups have on external hard drive, they're 85 gb. expected hard drive on imac have less 100 gb of space used on it, guys have idea taking other 160 gb of space? appreciated.

 

what "other" in storage tab? eating space? theseb

find out, hard drive capacity being used, can use following free applications:

• diskinventory x
• omnidisksweeper
• jdisk report
• grandperspective

 

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