Ubuntu – How to check integrity of system if Wubi not shut down properly

When this happens on a Wubi installation, it is is generally due to:

1. Minor partition table errors
2. A MBR partition table but some leftover GPT partition table data
3. Unsupported raid

Probably the best way to diagnose would be to boot an Ubuntu CD as a live CD (select Try Ubuntu without installing) and run the bootinfoscript.

You can also just hit CtrlAltF1 when you get that error to drop to a terminal and run: sudo parted -l and sudo fdisk -l The first will tell you if there are partition table errors. The second will tell you if there is some leftover GPT data (usually if you reuse a disk from a Mac). If you need to remove this GPT data you can use fixparts found here.

For example, this sudo fdisk -l output shows that a GUID partition table is detected, but does not seem to be used:

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition Boot Start Sector End Sector # of Sectors Id System

/dev/sda1 * 2,048 206,847 204,800 7 NTFS / exFAT / HPFS
/dev/sda2 206,848 307,202,047 306,995,200 7 NTFS / exFAT / HPFS
/dev/sda3 307,202,048 976,771,071 669,569,024 f W95 Extended (LBA)
/dev/sda5 307,204,096 614,404,095 307,200,000 7 NTFS / exFAT / HPFS
/dev/sda6 614,406,144 976,771,071 362,364,928 7 NTFS / exFAT / HPFS


GUID Partition Table detected, but does not seem to be used.

Running sudo blkid may provide information regarding any fakeraid partitions (there are probably better tools for checking the raid setup but I'm not familiar with these).

From the error messages, it appears that a file download has failed -- the file was corrupt due to transmission errors. These things are quite rare, but happen. Try to run the whole process again. It should show you this error in a nicer and clearer way and then not try to continue and get all kinds of other funny errors, but the program you're using is apparently not very well-written with regard to such error-handling.

Potentially useless but somewhat interesting background info: this is what the "invalid MD5" message means: MD5 is a so-called hashing algorithm, which computes a checksum value based on some data (the downloaded file). It is then compared to the known correct checksum value. MD5 checksums differ a lot even if just a single little piece of the data is different, and that is what has happened here.