Yes. It does happen if it has never happened to you and if it has happened to you before; here I discuss how to correct the error and force TWRP or ClockWorkMod Recovery to bypass the MD5sum check stage while restoring an android device from a previous backup file.
Sometimes, a backup could be so important to you that you would not want to loose the backup at any cost. Maybe because it's the only back-up for that phone that you have left or because it's the only perfectly working backup you have left and the MD5sum mismatch is preventing you from flashing the backup back on the phone or any other phones alike.
How Does MD5sum Works?
MD5sum is a security measure usually used to check the validity of a file. It is usually generated when the file is being created. The time, the date and some other factors are being considered while the MD5sum is being generated.In other words, the same factors that are been considered when an MD5Sum is being generated are also considered in validating a file.
2 Ways to Bypass MD5Sum Check of Android Backup File
Method 1: the Backdating MethodThis method involves you to backdate the time on the android device on which you wish to restore the backed up file.
How Do I Backate?This method is especially good for backups made with ClockWorkMode and TWRP recovery because you can easily know the time and date the backup was made by simply looking at backup folders' name.
1- Go to Settings >> Time And Date and reset the date on the Android device to an earlier time, close to when the backup was made.
E.g if the backup was made on an android device whose date was 12-12-2010 then, you should reset your android phone's date to 13-12-2010.
Method 2: MD5Sum Erase Method
This method simply erases all the MD5sum files thereby forcing either ClockWorkMod Recovery or TWRP recovery to overlook the MD5sum files and skip the MD5sum check stage.
How Do I Do this?
1- Download any of the file browsers available on the market. I use ES Explorer.
2- Navigate to the backup folder.
3- Locate the backup folder.
In TWRP Recovery: Lunch your File browser (e.g ES) >> the Disk (SD Card or Internal Memory) >> TWRP Folder >> Backups >> The Backup Folder you wantOr
In ClockWorkMod Recovery: Lunch your File browser (e.g ES) >> the Disk (SD Card or Internal Memory) >> ClockWorkMod Folder >> Backups >> The Backup Folder you want4- In the Backup folder, locate any of the files whose name ends with .md5 -that is the file we need.
5- Tap to open it. A list pops up, simply select "Text" then, it will open up using either the explorer or your native .txt application.
6- Highlight and erase everything in the folder then, save it. That's all and good luck.
You can now go back and flash the backup file on any compatible phones.
Source: Correcting MD5Sum Check Error