If you need to repair PDF, there are multiple options you can try to get it done. Unfortunately, it is not a foolproof process, but we are going to see different ways to do it completely free of charge, and that you at least have the possibility to try it. Let’s see it.
Index of contents
- Repair corrupt PDF, why does a PDF file get corrupted?
- Methods to repair PDF
- Repair PDF with Acrobat?
- online tools
- Software to repair PDF
- It all depends on the damage to the file
Repair corrupt PDF, why does a PDF file get corrupted?
A PDF file can become corrupted so that it is completely impossible to open. When it gets corrupted, it means that its internal content is changed. Let’s remember that a PDF can combine inside binary data (zeroes and ones without meaning) with text (readable directly when viewing the internal code). In both cases, but especially in binary data, a simple modification can be catastrophic and make it impossible to read the information.
And what exactly can cause such file corruption? The most normal thing is that it is a network or disk error, that is, either when downloading the file or when trying to access it with a defective hard disk, some bits inside the file are changed, and PDF readers they will no longer be able to read it.
It can also be due to other causes, such as malware attacks, using incompatible software that may modify the file when trying to open it, etc. Or we can even directly generate a corrupt PDF because of our editing program.
Another possibility is that the file was generated with incorrect attributes for the different objects in the PDF, or that it is generated in a way that some readers do not understand its content and others do. By the way, we indicate that you should try your corrupt file with several PDF readers , to see if this is the problem. If it is, it is usually the easiest error to fix.
Methods to repair PDF
In all these cases, we may be able to fix PDF corruption by making use of specialized tools. We are going to show you several, all free, and some online. Keep in mind that, in online tools, we “lose” control of our files, so avoid using them with confidential files.
Some of the processes that use these tools are:
- Retrieve crosstab from PDF
- recover pages
- rebuild the objects
- Rebuild the sources
Repair PDF with Acrobat?
Adobe Acrobat is undoubtedly the most famous PDF program of all time, whether we are talking about the Reader DC version (free) or the Pro version (paid and with editing functions). Also, Adobe is the creator of PDFs. It makes sense to think that Acrobat can repair PDF, but it doesn’t.
This feature simply does not exist in Adobe Reader. However, there are two things we can keep in mind:
- According to Adobe, updating Acrobatmay be enough to fix a PDF file that won’t open. But it is very unlikely that this is the problem.
- What is perhaps more likely is that there are PDF files that won’t open in other programs, but will open in Acrobat. This sometimes happens with certain very large PDFs with many forms and features. We recommend you download Acrobat Readerand try it out.
If you actually manage to open the PDF only with Acrobat, what you can do is export it again or print it saving to PDF from the program itself, and thus be able to open it later. But if it is a question of functionalities, you are going to lose them.
online tools
The alternative to Acrobat, which we could consider the logical solution to repair PDF, is to try online tools. As we said before, it is better to avoid these methods for sensitive files. The tools that we indicate to you affirm not to save the files on their servers, but we will never know 100% the level of confidentiality of the data.
The first tool that we are going to try is the one from I Love PDF , this page is without a doubt one of the best for all our needs with PDF files, and for that reason we have considered that its repairer could work well. It is completely free and they clearly indicate that they do not save the files on their servers for more than 2 hours to allow us to download them. In addition, they promise to meet all safety standards.
Other online PDF recovery services:
- PDF2go
- A meeting
- AvePDF
Software to repair PDF
Have you not managed to repair your PDF or the data is too sensitive to send it online? The last alternative left to us is to use a specific PDF repair software. Here, as always, we must avoid any potentially malicious software, so we have searched for those that are more reliable.
One of the most famous is PDF Repair Toolbox , but it is not free: in its DEMO it will only recover the first page. In general, this is what happens with almost all the PDF repair programs that we find: even if they pretend to be free, what they will do is show us the content of the fixed PDF and ask us to pay immediately .
It happens, for example, with PDF Fixer . If you only need a specific piece of information from the PDF, you can try to repair it and, if it succeeds, take a screenshot of the preview. That way you get rid of paying.
Finally, we are going with an open source option that could also render our PDF without problems. This is Ghostscript . You can use it by opening a terminal in Windows in the folder where it is downloaded (with right click inside the file explorer in Windows 11) and putting the following command:
gswin32c.exe -o repaired.pdf -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress corrupted.pdf
Being “corrupted.pdf” the name of the corrupted file. This is an answer provided on Superuser (Stack Exchange) .
It all depends on the damage to the file
The success of all these processes depends on how much damage there is to the file, and how serious it is. If the file is highly corrupted, no “household” software is going to fix it, sadly.
We recommend reading our guide on what software is .
Other cases in which we are going to have problems when recovering a PDF file will be those in which it is protected by a password. Normally, it is done using the AES-256 algorithm . This is simply unbreakable, so the only way to get the PDF to open is by brute force , the heaviest and most difficult method, especially if you don’t know anything about what the password looks like, in which case it could take years ( or centuries ). ) in deciphering i