The issue may simply be that your adobe acrobat reader software is not up to date. the files adobe requires to run may have become corrupted. 1k views 1 year ago change pdf icons back to default adobe reader/ acrobat: stop pdf files opening in invalid format. select pdf file or drop pdf here analyze and repair pdf files. could you please also share the source from where you are trying to download file. upload a corrupt or damaged pdf and we will try to fix it. 1 correct answer adorobat • adobe employee, hi alk, sorry for the delay in response. are you experiencing this issue in downloading other pdf as well? hi pdf invalid stuart taylor, please let us know the dot version of adobe application and os you are using? 7k subscribers subscribe 5. recover content and data from corrupt files with ease. are you downloading file on desktop or mobile device? regards, meenakshi upvote translate. if any updates are available, install them and then try reopening your pdf on the app.
in which case, go to help > repair installation. pdf showing invalid format pc shastra 52. launch adobe acrobat reader and go to help > check for updates. as per the issue description mentioned above, you are facing issue with certificate signature on the pdf, is that correct?