To verify the root of the error, please paste the output of a couple of commands here. You need rootsh installed!For best results use copy'n'paste to prevent typos, especially for small 'L' and number 'one'.

ok i will try

when i connect my n900 to Pc i can see memory and i can copy file on phone but when i go to File manager on my mob its sey (no files/folders) in my memory say Deviance (memory card corrupted)

There might be some kind of corruption, that maemo considers as blocker while your PC uses some workaround. By the way, which OS does your PC work on?

The output looks good so far. Please install the 'rootsh' package via the Application Manager for the last three commands of my former post to work. These are essential to repair the file system of the internal memory card.

i hava windows 7 x64 on my pc,ok i will install rootsh and i will tell you result after

BusyBox v1.10.2 (Debian 3:1.10.2.legal-1osso30+0m5) built-in shell (ash)
Enter 'help' for a list of built-in commands.

~ $ df
Filesystem 1k-blocks Used Available Use% Mounted on
rootfs 233344 130708 98356 57% /
ubi0:rootfs 233344 130708 98356 57% /
tmpfs 1024 76 948 7% /tmp
tmpfs 256 84 172 33% /var/run
none 10240 72 10168 1% /dev
tmpfs 65536 4 65532 0% /dev/shm
/dev/mmcblk0p2 2064208 158592 1800760 8% /home
/home/opt 2064208 158592 1800760 8% /opt
/opt/pymaemo/usr/lib/python2.5
2064208 158592 1800760 8% /usr/lib/python2.5
/opt/pymaemo/usr/share/pyshared
2064208 158592 1800760 8% /usr/share/pyshared
/opt/pymaemo/usr/lib/pyshared
2064208 158592 1800760 8% /usr/lib/pyshared
/opt/pymaemo/usr/share/python-support
2064208 158592 1800760 8% /usr/share/python-support
/opt/pymaemo/usr/lib/python-support
2064208 158592 1800760 8% /usr/lib/python-support
~ $ mount
rootfs on / type rootfs (rw)
ubi0:rootfs on / type ubifs (rw,bulk_read,no_chk_data_crc)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
tmpfs on /tmp type tmpfs (rw,noatime,size=1024k)
tmpfs on /var/run type tmpfs (rw,nosuid,noatime,size=256k,mode=755)
none on /dev type tmpfs (rw,noatime,size=10240k,mode=755)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,noatime,size=65536k)
/dev/mmcblk0p2 on /home type ext3 (rw,noatime,errors=continue,commit=1,data=writebac k)
/home/opt on /opt type none (bind)
nodev on /sys/kernel/debug type debugfs (0)
/opt/pymaemo/usr/lib/python2.5 on /usr/lib/python2.5 type bind (bind)
/opt/pymaemo/usr/share/pyshared on /usr/share/pyshared type bind (bind)
/opt/pymaemo/usr/lib/pyshared on /usr/lib/pyshared type bind (bind)
/opt/pymaemo/usr/share/python-support on /usr/share/python-support type bind (bind)
/opt/pymaemo/usr/lib/python-support on /usr/lib/python-support type bind (bind)
~ $ sudo gainroot
Root shell enabled


BusyBox v1.10.2 (Debian 3:1.10.2.legal-1osso30+0m5) built-in shell (ash)
Enter 'help' for a list of built-in commands.

/home/user # sfdisk -l

Disk /dev/mmcblk0: 977024 cylinders, 4 heads, 16 sectors/track
Units = cylinders of 32768 bytes, blocks of 1024 bytes, counting from 0

Device Boot Start End #cyls #blocks Id System
/dev/mmcblk0p1 1 884864 884864 28315648 c W95 FAT32 (LBA)
/dev/mmcblk0p2 884865 950400 65536 2097152 83 Linux
/dev/mmcblk0p3 950401 974976 24576 786432 82 Linux swap / Solaris
/dev/mmcblk0p4 0 - 0 0 0 Empty
/home/user # fsck -af /dev/mmcblk0p1
fsck 1.41.3.maemo0 (12-Oct-2008)
dosfsck 2.11, 12 Mar 2005, FAT32, LFN
Currently, only 1 or 2 FATs are supported, not 6.

/home/user #

This is resault but i can still access to memory

Thanks and I appreciate your interest to help! I solved the problem with testdisk I lost my data but important that everything is working normally
This solved the matter---http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step