asp.net - System.Web.UI.ViewStateException ,Invalid viewstate -

my website throwing below exceptions everyday , couldn't find solution. did few research in web , far. adding below option aspx won't solve problem.

validaterequest="false" enableeventvalidation="false" viewstateencryptionmode="never" enableviewstatemac="false"

also, referral url correct url , have no idea how redirect 2 (same) parameters. there no such link in referral page. please help.

error log

url : http://www.abcd.com/company-details.aspx?com=asia-pacific-pte-ltd&com=asia-pacific-pte-ltd  referral url : http://www.abcd.com/companies/asia-pacific-pte-ltd/  inner exception type: system.web.ui.viewstateexception  inner exception: invalid viewstate. client ip: 192.162.19.193 port: 1966 user-agent: opera/9.80 (windows nt 6.1; wow64; mra 6.0 (build 6001)) presto/2.12.388 version/12.11 viewstate: /wepdwullteymtaymty3ndapzbycagmpzbyozg8qdxyghg1eyxrhvgv4dezpzwxkbqddb3vudhj5hg5eyxrhvmfsdwvgawvszaunq2xlyw5fq291bnryer4lxyfeyxrhqm91bmrnzbavcgnbbgwfq2hpbmejsg9uzyblb25nbuluzglhculuzg9uzxnpyqhnywxhexnpyqtqaglsaxbwaw5lcwltaw5nyxbvcmuivghhawxhbmqhvmlldg5hbruka0fsbavjagluyqlob25nlwtvbmcfaw5kawejaw5kb25lc2lhcg1hbgf5c2lhc3boawxpchbpbmvzcxnpbmdhcg9yzqh0agfpbgfuzad2awv0bmftfcsdcmdnz2dnz2dnz2dkzaibdxapfgyfaauisw5kdxn0cnkfaquoq2xlyw5fsw5kdxn0cnkfamdkebxfagnbbgwsqwr2yw5jzwqgtwf0zxjpywxzc0fkdmvydglzaw5nckflc3rozxrpy3mlqwdyawn1bhr1cmukqwdyawn1bhr1cmuglsbbz3jpy3vsdhvyywwgtwfjagluzxj5g0fncmljdwx0dxjlicygrm9vzcbqcm9kdwn0cxbbaxity29uzgl0aw9uaw5nhufpci1mawx0cmf0aw9uicyguhvyawzpy2f0aw9ub0fpcnbvcnqjqwx1bwluaxvtfefuywx5dgljywwgrxf1axbtzw50gkfuywx5dgljywwgsw5zdhj1bwvudgf0aw9ufufuywx5dgljywwgvgvjag5vbg9nerzbbmqgsw50zxjpb3igrgvzawduzxjzeufuaw1hbcbqcm9kdwn0aw9ucefudglib2r5kufwc...  inner source:   exception type: system.web.httpexception  exception: state information invalid page , might corrupted.  stack trace: @ system.web.ui.viewstateexception.throwerror(exception inner, string persistedstate, string errorpagemessage, boolean macvalidationerror) @ system.web.ui.hiddenfieldpagestatepersister.load() @ system.web.ui.page.loadpagestatefrompersistencemedium() @ system.web.ui.page.loadallstate() @ system.web.ui.page.processrequestmain(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint) @ system.web.ui.page.processrequest(boolean includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint) @ system.web.ui.page.processrequest() @ system.web.ui.page.processrequest(httpcontext context) @ asp.exhibition_details_aspx.processrequest(httpcontext context) in c:\windows\microsoft.net\framework64\v2.0.50727\temporary asp.net files\root\0f461847\442b0502\app_web_bfjqxdef.20.cs:line 0 @ system.web.httpapplication.callhandlerexecutionstep.system.web.httpapplication.iexecutionstep.execute() @ system.web.httpapplication.executestep(iexecutionstep step, boolean& completedsynchronously) 

update have fixed error compressing viewstate below link http://www.codeproject.com/articles/14733/viewstate-compression

and fixed invalid length base-64 char array error replacing original method this.

protected override object loadpagestatefrompersistencemedium()     {         string viewstate = request.form["__vstate"];         viewstate = viewstate.replace(" ", "+");          int mod4 = viewstate.length % 4;         if (mod4 > 0)         {             viewstate += new string('=', 4 - mod4);         }         byte[] bytes = convert.frombase64string(viewstate);         bytes = compressor.decompress(bytes);         losformatter formatter = new losformatter();         return formatter.deserialize(convert.tobase64string(bytes));     } 

thanks :)

i sorry your site did not have anything, , need re-enable eventvalidations possible.

what see an attempt hack site sending many test numbers viewstate trying find hash key.

the ip give have big list of activity last few days.

now, alternative may cause error breaking of viewstate. can compress , split it if have big viewstate. can disable controls not needed. can add log see inside what's going on right on base page.