重用 Ubuntu Live USB

我使用Start Up Disk Creator创建了一个 Ubuntu 15.04 Live USB 。它工作得很好；完全没有问题。

但是，我现在使用的 U 盘不能用作存储设备。它仍然会启动 Ubuntu，但是当正常插入时，它根本不会出现在 Nautilus 中。将其插入我的 MacBook Pro 会发出有关无效文件系统的警告。

dmesg插上电源后运行

[  123.912989] usb 1-3: new high-speed USB device number 7 using xhci_hcd
[  124.043543] usb 1-3: New USB device found, idVendor=4146, idProduct=ba65
[  124.043552] usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  124.043556] usb 1-3: Product: USB Mass Storage Device
[  124.043560] usb 1-3: Manufacturer: PRETEC UG-02GB
[  124.043563] usb 1-3: SerialNumber: 5dd1c2372a6703
[  124.046014] usb-storage 1-3:1.0: USB Mass Storage device detected
[  124.046247] scsi host7: usb-storage 1-3:1.0
[  125.044940] scsi 7:0:0:0: Direct-Access     Pretec   UltimatGuard     6.00 PQ: 0 ANSI: 2
[  125.045864] sd 7:0:0:0: Attached scsi generic sg3 type 0
[  125.046317] sd 7:0:0:0: [sdc] 3947016 512-byte logical blocks: (2.02 GB/1.88 GiB)
[  125.046445] sd 7:0:0:0: [sdc] Write Protect is off
[  125.046449] sd 7:0:0:0: [sdc] Mode Sense: 00 00 00 00
[  125.046580] sd 7:0:0:0: [sdc] Asking for cache data failed
[  125.046584] sd 7:0:0:0: [sdc] Assuming drive cache: write through
[  125.180958]  sdc: sdc1 sdc2
[  125.182353] sd 7:0:0:0: [sdc] Attached SCSI removable disk

注意请求缓存数据失败- 这是一个错误吗？

磁盘出现在 as 的输出中lsblk（为清楚起见，省略了sdc
详细信息）sdasr0

NAME    MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sdc       8:32   1   1.9G  0 disk 
├─sdc1    8:33   1   1.1G  0 part 
└─sdc2    8:34   1   2.2M  0 part 

磁盘也出现在输出中sudo lshw -class disk

  *-disk                  
       description: SCSI Disk
       physical id: 0.0.0
       bus info: scsi@7:0.0.0
       logical name: /dev/sdc
       size: 1927MiB (2020MB)
       capabilities: partitioned partitioned:dos
       configuration: logicalsectorsize=512 sectorsize=512 signature=1cae5859

U盘有问题吗？

它不是因为它是可启动的而安装的吗？

将其转回“普通”USB 盘（即不是可引导安装盘）的最佳/正确方法是什么？

编辑：使用启动磁盘创建器的擦除磁盘选项会显示此消息

org.freedesktop.DBus.Python.GLib.Error: Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/dbus/service.py", line 707, in _message_cb
    retval = candidate_method(self, *args, **keywords)
  File "/usr/share/usb-creator/usb-creator-helper", line 274, in Format
    part.call_set_flags_sync(boot_dos_flag, no_options, None)
GLib.Error: udisks-error-quark: GDBus.Error:org.freedesktop.UDisks2.Error.Failed: Error setting partition flags on /dev/sdc2: Command-line `parted --script "/dev/sdc" "set 2 boot off"' exited with non-zero exit status 1: Warning: The driver descriptor says the physical block size is 2048 bytes, but Linux says it is 512 bytes.
 (0)

但磁盘现在确实出现在 Nautilus 中。但是，它不是空的，它上面有一些 EFI 引导的东西。