There are a few common file system or drives errors. They can happen during system boot up, log in or when you try to access a drive. You would normally get the following error messages:

• Missing Operating System
• No ROM Basic – System Halted
• Boot Error Press F1 to Retry
• Invalid Drive Specification
• Invalid Media Type
• Hark Disk Controller Failure

Missing Operating System

This error indicates problems in the master boot record or partition table entries. The partition table entries may be pointing to a sector that is not the actual beginning of a partition. Invalid BIOS settings, which sometimes is triggered by a dead or dying battery, could cause this error. You will get this error when MBR is damaged by virus. The trouble occurs because there is no active partition found in the partition table.

You can solve this problem by correcting the invalid BIOS settings. The BIOS settings for drive parameters and LBA translation must be set to the same values as when the drive was partitioned and formatted to read the drive correctly. You can try FDISK/MBR to repair a broken MBR on a FAT drive or FIXMBR with a NTFS drive. Other types of damage require more sophisticated use of a disk editor utility or repartitioning and reformatting the drive to start over.

No ROM Basic – System Halted

For an AMI BIOS, when the boot sector or master boot record of the boot drive is damaged or missing, you will get this error. You may also get this error when the boot drive has been improperly configured or is not configure at all in the BIOS. In this case, data in the partition might be valid and undamaged but no bootable partition exists.

For IBM systems, it would normally drop into a built-in BIOS versions of BASIC if it is having the similar problem. However most non-IBM BIOS manufacturers did not license this code from Microsoft. so, they would display this cryptic massage instead of dropping into BASIC. The typical solution to this problem is to run FDISK and set the primary partition as active because the most common cause of this type of error is a failure to set at least one partition as active (bootable). If this is not the problem, the solution is to repair the damaged MBR or correct the improper BIOS settings.

Boot Error Press F1 to Retry

when the hard disk is missing a master boot record or boot sector or when there is a problem accessing the boot drive, you may get this error, which is generated by the Phoenix BIOS. It is a problem similar to NO ROM Basic does on an AMI BIOS. No active partition is defined is the most common cause of this message.

Invalid Drive Specification

This error occurs when you attempt to log in to a drive that has not been partitioned or for which the partition table entry has been damaged or is incorrect. You can check the existing partition using FDISK or use FDISK to partition the drive. If they are damaged, you probably should use a data recovery tool such as REMO to correct the problem.

REMO is a Mac Recover Software that could also be used for Mac file Recovery. It could recover data on a failed hard drive and recover formatted memory card. It could also be used on Windows.

You can solve the problem by repartition the drive from scratch. However this could overwrite existing data on the drive.

Invalid Media Type

This indicates the partition table is valid, but the volume boot sector, directory, or file allocation tables are corrupt, damaged, or not yet initialized. For example, you would receive this error if you tried to access a drive that had been partitioned but not yet formatted. The format command is what creates the volume boot record (VBR), file allocation tables, and directories on the disk.

A data recover utility is required to solve this problem. Another solution could be redoing the high-level format on the drive. Because high-level formatting does not actually destroy the data, one technique to recover is to high-level format (OS Format) the volume and then immediately unformat it using the unformat utility.

Hard disk controller Failure

This message indicates the hard disk controller has failed, the hard disk controller is not set up properly in the BIOS, or the controller can not communicate with the attached drives (such as cable problems).

The solution is to look into the drive installation and make sure that the cables to the drive are properly installed, the drive is receiving power, it is spinning, and the BIOS setup definitions are correct. If all these are correct, the drive, cable, or controller may be physically damaged. Change them with know-good spares one by one until the problem is resolved.

Recovery data from flash memory devices such as USB keychain drives and card used in the digital cameras and digital music players come be a challenging task. From a user point of view, these devices are similar to the conventional disk drives. They have file allocation tables similar to those found on floppy disks and can usually be formatted through the Windows Explorer. Many data recovery programs are not able to recover data from these drives, especially when the devices have been formatted, even though these programs work well with conventional drives.

Under several conditions, data loss can occur with a flash memory device. Some of them, such as formatting of the media or deletion of one or more photos or files, can occur when the device is connected to the computer through a card reader or whether flash memory device is inserted into a digital camera. When photos are deleted, the file locations and name listings in the file allocation tables are changed in the same way as when file are deleted from magnetic media: The operating system marks the file as deleted and changes the first character of the filename to a lowercase sigma. Undelete programs that support removable devices can retrieve deleted files on flash memory devices the same way that they retrieve deleted files from magnetic media.

However it is much more difficult to recover data from a formatted flash memory device, whether it has been formatted by a digital camera or through Windows. Because the flash memory devices are accessible only from within the Windows GUI and command-line programs are designed to work with BIOS-compatible devices such hard and floppy drives, traditional unformat programs are not useful for cases like these.

Formatted Data Recovery

You can use data recovery tools, for instance REMO Recover, if you would like to recover data from a formatted flash memory card. REMO Recover (Windows) is an integrated utility suit that could be used to retrieve data from hard drive and flash memory card.. In addition , it come with features such as email backup. It may be used to fix corrupt pst as well.

The following changes occur to the disk when a file is deleted:

• Windows replace the first character of the filename with a lowercase sigma character.
• Two entries, one for the deleted file and one for its associated long file name (LFN) are created in file allocation table. These include:
• Erased. An erased file
• Del LFN. An LFN belonging to an erased file.

The clusters in which the file is stored are marked by the operating system as clusters that are accessible for reuse. Because of this, these clusters may be overwritten by new data if the undelete action is not carried out immediately. Depending on the file type, the file could be destroyed even when just one cluster is overwritten.

File Undelete:

There are four steps in undelete process:

• The original file name will be restored.
• The clusters where the file is stored would be identified.
• FAT records for the file will be recreated.
• LFN records for the file would be linked to the file.

Of these four steps, the most critical are locating the clusters used by the file and recreating the FAT entries for the file. However restoring a deleted program file to its original name is important. If not the program would not function correctly. Restoring the LFN entries enables a Windows users accustomed to long filenames to more easily use the file.

How to Recover Data

You can use data recovery tools, for example REMO Recover, if you would like to undelete file. REMO Recover (Windows) is an integrated utility suit which can be used to retrieve deleted files. It also has email recovery feature that could be used to recover outlook emails.

Recovering lost data can be as simple as opening the Window’s Recycle bin, or it might require spending hundreds of dollars on specialized data recovery software or services. For most serious cases, your hard drive may have to be delivered to data recovery center. The factors that affect the degree of difficulty of data recovery are the following:

• How and when the data is deleted.
• What is the file system of the hard drive?
• The type of hard drive. Is it a magnetic, magnetic, optical, magneto-optical, or flash memory media?
• Which operating system is used?
• Is there any data protection software installed?
• Any physical damages to the hard drive?

The Windows Recycle Bin

When you delete a file in the Windows, it is deleted from its normal location and it is sent to Recycle bin. Windows reserves about 1% of hard drive space for Recycle bin and whatever is sent to the Recycle bin is actually protected from being overwritten by the system. However, when deleted file exceeds the capacity of Recycle bin, windows will overwrite the older files in Recycle bin. As a result, you are more likely to retrieve the file if you discover it has been sent to Recycle bin accidentally. To retrieve a file from Recycle bin, open the Recycle bin, select the file, right click it and select Restore. Windows will list the file in its original location and removes it from the Recycle bin. If a file is deleted when you hold down the Shift key, the Recycle bin is bypassed. Retrieving lost data at this point requires data recovery software.

Recover Files that Are Not in the Recycle Bin

The Recycle bin is a useful first line of defense against data loss but it can be bypassed when you select file for deletion. Besides, files stored in Recycle bin are eventually kicked out by the newer deleted files. If you want to retrieve files that are not in the Recycle bin, it is necessary to use data recovery software such as REMO Recover. REMO Recover (Windows) is an integrated utility suit for windows and Mac that offers many features which include deleted partition recovery and laptop hard drive recovery. It is also en email recovery software which would recover the lost e-mails.

Recovering Data from Partitioned and Formatted Drives

When a hard disk, floppy disk, or removable-media drive has been formatted, its file allocation table, which is used to determine the location of the files, is lost. The original file system and partition information is lost if a hard drive has been repartitioned with FDISK or another partitioning program. In such cases, more powerful data recovery tools much be used to retrieve data. To retrieve data from an accidentally formatted drive, you have two options:

• use an application that could unformat the drive
• use a software program that could bypass the newly created FAT and browse disk sectors directly to discover and retrieve data.

To retrieve data from a drive which has been partitioned, you need to make use of a program that will read disk sector directly.