i have only 1 address and the version is 0.5.19
In that case I'm not sure what the problem is. I haven't used multibit classic to make transactions for a long time because its maximum allowed fees are often too low to get fast confirmations in today's overloaded network.
You could try using these instructions to export your private key from multibit and import it into electrum. If multibit is stopping you exporting your key by greying out the menu then try closing it, turning your internet connection off, then starting multibit up again.
Start multibit, select the wallet containing your coins, then click "tools", then select "export private keys" as shown in the screenshot.
A new tab should open like the one below. Select "do not password protect export file" at the bottom of the window, then click the "export private keys button".
Click the windows start button, then copy and paste the line of text below into the search box that appears, then press the enter key to open the hidden folder containing your multibit wallet files.
%appdata%\Multibit
This is what your search box should look like after you have copied and pasted the line above into it.
Inside the folder that opens there should be a file with an extension ending in ".key". Open it in notepad and copy your wallet's private key. In the example file below the private key is the bit in red.
Quote
# KEEP YOUR PRIVATE KEYS SAFE !
# Anyone who can read this file can spend your bitcoin.
#
# Format:
#[[]]
#
# The Base58 encoded private keys are the same format as
# produced by the Satoshi client/ sipa dumpprivkey utility.
#
# Key createdAt is in UTC format as specified by ISO 8601
# e.g: 2011-12-31T16:42:00Z . The century, 'T' and 'Z' are mandatory
#
KwUVsx4nd4UTHUtNTPnLEEqapCFvNiBrVASBZPa1ZvStQbUD87VK 2017-03-26T01:36:45Z
# End of private keys
# Anyone who can read this file can spend your bitcoin.
#
# Format:
#
#
# The Base58 encoded private keys are the same format as
# produced by the Satoshi client/ sipa dumpprivkey utility.
#
# Key createdAt is in UTC format as specified by ISO 8601
# e.g: 2011-12-31T16:42:00Z . The century, 'T' and 'Z' are mandatory
#
KwUVsx4nd4UTHUtNTPnLEEqapCFvNiBrVASBZPa1ZvStQbUD87VK 2017-03-26T01:36:45Z
# End of private keys
After you get your private key use these instructions to import it into electrum.
http://docs.electrum.org/en/latest/faq.html#can-i-import-private-keys-from-other-bitcoin-clients
Multibit classic's maximum allowable fees aren't high enough for dealing with today's massive backlog of unconfirmed transactions. It's best to import the private key into electrum, enable dynamic fees in it, and spend your coins from there. That way you will get fast confirmations.
